skywatcher · 2020. 12. 6. · nobel-worthy science. in the summer of 1974, radioastronomer joseph...
TRANSCRIPT
1
Club Officers
President David Olsen 208Four68-79 four-seven BoiseAstroltagtoutlookcom
Vice-President Jim McMillian basvicepresidentltagtgmail
Secretary Pamela Olsen bastrossecretaryltagtgmail
Treasurer Tamara Hunter bastrostreasurerltagtgmail
AL-Cor Dr Irwin Horowitz basalcorltagtgmail
Publicity Leif Edmondson BASpublicrelationsltagtyahoo
Webmaster Bailey Nielsen bastroswebmasterltagtgmail
ISP Coordinator Jeffrey Creed BASispcoordinator ltagtgmail
Members-at-Large Carol Smith Randy Holst
Education and Boise State University Liaison Dr Brian Jackson httpwwwastrojackcom
Member - Astronomical League amp
NASA Night Sky Network
wwwboiseastroorg
httpsgroupsiogBoiseAstro
Newsletter Editor Loretta J Cannon BASnews42ltagtgmail
Presidentrsquos Message Our Holiday Party for 2020 has been cancelled due to the Corona Virus Pandemic This makes it a little difficult for elections but we have a solution Please watch our social media accounts on Groupsio Facebook and twitter boiseastro for the BAS officer elections announcement Our December BAS board meeting will be held on Wednesday December 9 2020 at 700 pm via Zoom teleconference Our next BAS general membership meeting will be held Friday December 11 2020 at 700 pm via Zoom teleconference This monthrsquos guest speaker will be Asst Prof Heidi Wu from Boise State University She will be speaking on the subject Why is our Universe Accelerating The two star parties scheduled for the month of December have also been cancelled The biggest event for December is the conjunction of Saturn and Jupiter when they will be about a tenth of a degree apart in the sky on the evening of the 21st at 700 pm This will of course be captured by astrophotographerrsquos in the club and weather permitting you can set up your telescope in your own back yard Until next month clear skies David Olsen President Boise Astronomical Society
----------------------------------------------------------------------------------------------------
Hubble Image from December 25 2009
ldquoThe dwarf galaxy NGC 4214 is ablaze with young stars and gas clouds This image captures intricate patterns of glowing hydrogen shaped during the star-birthing process cavities blown clear of gas by stellar winds and bright stellar clustersrdquo
Credit NASA ESA and the Hubble Heritage (STScIAURA)-ESAHubble
Collaboration Acknowledgment R OConnell (University of Virginia) and
the WFC3 Scientific Oversight Committee
Would you like to JOIN the Boise Astronomical Society See Last Page
SkyWatcher is the Newsletter of the Boise Astronomical Society and is published electronically once a month SkyWatcher copy 2020 by Loretta J Cannon for the Boise Astronomical Society All Rights Reserved Images used in this newsletter unless otherwise noted are in the public domain or are courtesy of NASA Wikimedia or are BAS File Photos Non-Public images and articles used are with the permission of the respective author who holds the copyright Names of the Full Moon are from the Algonquin Nation
SkyWatcher The Newsletter of the Boise Astronomical Society December 2020
2
Sun Mon Tue Wed Thu Fri Sat
1 2 3 4 5 BSU
1st Friday Astronomy
see Calendar of Events
below
6 7 8 9 10 11 12 Last Quarter
Moon
Visible 45 darr
Age 2265 Days
BAS Board Meeting
700 pm via Zoom
BAS General Mtg
700 pm via Zoom
see Calendar of Events
below
13 14 15 16 17 18 19 New Moon rarr
Visible 0
Age 2933 Days
Geminid Meteor Shower
This yearrsquos
BEST meteors
20 21 22 23 24 25 26 First Quarter rarr
Moon rarr
Visible 45 uarr
Age 693 Days
Jupiter - Saturn
Conjunction
see Calendar of Events
below
Ursid Meteor Shower
early in the
morning
UFS Alert
see Calendar
of Events below
27 28 29 30 31 Cold Moon
830 pm
Visible 100
Age 1510 Days
TABLE of CONTENTS Calendar of Events 3 Currents in Space 4 NASA Night Sky Notes 6
Phil Harringtonrsquos Cosmic Challenge 7 Dave Mitskyrsquos Celestial Calendar 10 Join BAS 14
December 2020 Calendar
3
Friday December 4 Boise State Physics First Friday Astronomy
ldquoNASArsquos Lucy Mission 1 Spacecraft 7 Trojan Asteroids 12 yearsrdquo by Dr Cathy Olkin Southwest Research Inst Online Lecture begins 730 pm (MT) httpwwwastrojackcomffa-lucy-mission
If you missed this presentation you can view it and other previous lectures online at httpwwwastrojackcom
Nov 6 2020 A Practical Guide to Time Travel by Prof Barbara Ryden Dept of Astronomy The Ohio State University Oct 2 2020 The Solar System Laboratory A Testbed for Exoplanet Studies by Dr Laura Mayorga Space Telescope Science Institute
Sept 4 2020 Peering Through the Haze Titanrsquos Fascinating Atmosphere and Surface by Darci Snowden Professor of Physics Central Washington University
Aug 7 2020 Sub-Orbital Ballooning Experiments and Education by Dr Paul Verhage Treasure Valley Math amp Science Center
July 3 2020 ldquoWhat are these yellowballsrdquo How citizen scientistsrsquo curiosity led to a new catalog of star formation tracers by Prof Katie Devine College of Idaho
June 6 2020 The Antikythera Mechanism by James Evans Professor of Physics University of Puget Sound
Scheduled for Jan 1 2021 The Discovery of Neptune by Prof Brian Jackson Dept of Physics Boise State University
----------------------------------------------------------------------------------------------------------------------------- ------ Friday Dec 11 BAS General Meeting guest speaker - Dr Heidi Wu Join us for our General Meeting and hear our guest speaker Asst Prof Heidi Wu Department of Physics at Boise State University She will be speaking on ldquoWhy is our Universe Acceleratingrdquo Her research at BSU involves using ldquogalaxy clusters to probe the composition of our Universerdquo You can learn more about her on her website httpshywugithubio This will be a fun evening
----------------------------------------------------------------------------------------------------------------------------- ------ Monday Dec 21st Jupiter and Saturn Conjunction This is the first Jupiter-Saturn conjunction to be observed since the year 2000 and the closest pairing since the year 1623 The next view-worthy close-up conjunction wonrsquot be until March 2080 This year the event falls on the winter solstice with the worlds looking like a double-planet low in the SSW sky near the horizon just after sunset a mere 01 degrees apart (15 of a full moon) Jupiter will be the brighter of the two with Saturn appearing as if a 1st-magnitude star (and if we could see the Milky Way in our sky the conjunction would be next to it) Earth amp Sky has a lovely comprehensive article on this astronomical event In this issue of SkyWatcher the NASA Night Sky Notes is about the exploration history of Jupiter and Saturn
----------------------------------------------------------------------------------------------------------------------------- ------ Thursday Dec 24 Annual UFS Alert For over 100 years there have been UFS sightings very late at night on December 24th across the United States and over much of Europe People who claim to have seen the Unidentified Flying Sleigh say it appears to be something out of Victorian times but up in the sky flying over the rooftops of homes Stranger still are the reports that eight caribou appear to precede the antique vehicle as it moves through the air Observers from rural areas claim to have heard a voice with the sighting a male voice reminiscent of a happy old grandfatherrsquos deep-throated laugh Even more odd in some cases objects mysteriously appear inside peoplersquos homes though doors and windows were locked There is nothing to be concerned about though Every confirmed sighting has resulted in feelings of peace joy and goodwill to all
Calendar of Events
4
by Loretta J Cannon
SAD NEWS FOR ASTRONOMY ndash ARICEBO TELESCOPE COLLAPSE
Some of you may have been heard the 900-ton instrument platform for the Arecibo main radio telescope crashed onto the 305-meter reflector dish at 755 am local time on December 1st No one was injured as operations had been halted four months ago when a support cable snapped on August 10th at 245 am local time This first cable break created a 100-foot long gash on the edge of the reflector dish Three months later on November 6th a main cable broke on the same support tower By November 19th the decision was made to decommission the telescope And then it fell The loss of this instrument is a heavy blow to the fields of planetary science atmospheric science and both radio and radar astronomy Wersquove also lost one of only two planetary radar facilities working with NASArsquos Near-Earth Object observing program to characterize optically-detected objects
At Right intact Arecibo telescope in 2018 [credit UCFAreciboNSF]
The Arecibo Observatory is comprised of not only the now-collapsed main 305-meter radio telescope but also a much smaller 12-meter radio telescope a LIDAR facility and world-class research and visitor centers The Observatory is currently managed by the University of Central Florida (UCF) in partnership with the Universidad Ana G Meacutendez and Yang Enterprises under the US National Science Foundation (NSF) The main radio telescope had been in operation for 57 years Built over a natural sinkhole the telescope lsquoheardrsquo first light in 1963 Prof William E Gordon of Cornell University
conceived the observatory in 1958 and after it was built Cornell University managed the site from 1963 until 2011 when the contract was awarded to SRI International Then in February 2018 management was granted to the UCF-led consortium [Herersquos a funny fact the silly people who write
for Britannicacom failed to check the facts their update for the collapsed telescope reports Cornell Univ is still managing the
site oops] Until 2016 Arecibo had been the worldrsquos largest filled-aperture telescope when Chinarsquos Five-hundred meter Aperture Spherical Telescope (FAST) went online A unique feature of Arecibo was its 2 megawatt transmitter as the telescope was also designed to study the Earthrsquos ionosphere At Left Damage caused by the first cable snap [credit UCF]
Over the last five and a half decades the Arecibo observatory has been involved in not only ground-breaking but also Nobel-worthy science In the summer of 1974 radioastronomer Joseph Taylor and graduate student Russell Hulse discovered the first binary pulsar providing evidence in support of Einsteinrsquos General Theory of Relativity a discovery for which they received the 1993 Nobel Prize in Physics Also in 1974 (when Frank Drake was the observatory director) a rsquoHellorsquo message was sent into space That was (and still is) the most powerful message sent from Earth The NASA SETI listening program at Arecibo ran from 1992-93 after which time university and private institutions used Arecibo for SETI studies Also in 1992 astronomer Alex Wolszczsan discovered the first exoplanet while at Arecibo In 2016 investigators discovered the first repeating fast radio bursts millisecond radio pulses that lsquoappearrsquo extra-galactic in origin In 2017 the discovery of two pulsars that undergo lsquoa cosmic vanishing actrsquo ldquoupended the widely held view that all pulsars are orderly ticking clocks of the universerdquo As part of NASArsquos Near-Earth Object (NEO) observing program after an NEO was
Currents in Space
5
identified by an optical telescope Arecibo was able to precisely characterize it ndash size shape composition speed trajectory ndash allowing NASArsquos Planetary Defense Coordination Office time to formulate risk management plans Finally in addition to its decades of searching for SETI signals mapping pulsars finding extra-galactic radio sources pinging near-Earth asteroids and making atmospheric observations of Earth Arecibo has also been featured in the films Golden Eye (1995) and Contact (1997)
As part of the decommissioning process drones flew over the telescope evaluating the damage Because of this we have aerial footage of the collapse courtesy of the Observatory and NSF There are two videos in this footage in the first you can hear the structure crashing down while the second is like watching a close-up disaster movie scene that slowly pans back to a wide shot of the devastation It is heart-breaking to watch the structure fall knowing all that went with it At Left Collapse on December 1 2020 [credit Prof Abel Meacutendez Arecibo (ProfAbelMendez)]
Even without the main telescope Arecibo Observatory will continue as an international research facility And on the planetary defense side of the equation NASArsquos Goldstone complex (one of
the Deep Space Network sites listening to our Voyagers) is the other radar facility fully capable of characterizing an NEO detected by a network of optical telescopes
-------------------------------------------------------------------------------------------------------------------
ldquoCOSMIC PURSUITSrdquo FOR DECEMBER I highly encourage you to check out Brian Ventrudorsquos Cosmic Pursuits for December where yoursquoll find this image and more
ldquoThe waxing crescent Moon below Jupiter and Saturn after sunset on Dec 16 2020 The two planets continue to move closer to each other until Dec 21 when they lie less than 01 degree apart their closest conjunction since 1623rdquo
[image produced using SkySafari 6 Plus software httpsskysafariastronomycom]
6
Visitors to Both Jupiter and Saturn by David Prosper Have you observed Jupiter and Saturn moving closer to each other over the past few months On December 21 the two worlds will be at their closest around 15 of a full Moon apart While the two gas giants may appear close in reality they are hundreds of millions of miles apart Despite this vast distance a select few missions have visited both worlds by using a gravity assist from giant Jupiter to slingshot them towards Saturn saving time and fuel Pioneer 11 was the first mission to visit both worlds Launched in 1973 the probe flew past Jupiter in late 1974 passing just 26400 miles above its stormy clouds In 1979 it became the first spacecraft to encounter Saturn Pioneer 11 took the first up-close photos of Saturn and its satellites and made many exciting discoveries including the detections of its magnetic field and a faint ldquoFrdquo ring before departing Saturn and eventually the solar system The Voyager missions quickly followed up taking a ldquoGrand Tourrdquo of the four largest and most distant planets in our solar system Both probes were launched within two weeks of each other in 1977 Voyager 1 flew past Jupiter in March 1979 discovering Jupiterrsquos faint ring and two new moons along with active volcanoes on Iorsquos surface The probe then flew past Saturn in November 1980 discovering five new moons a new ldquoGrdquo ring mysterious ring ldquospokesrdquo and ldquoshepherd moonsrdquo shaping the rings After a brief encounter with Titan revealed evidence of complex organic chemistry and liquid on the moonrsquos frigid surface Voyager 1 was flung out of the plane of the solar system Following close behind Voyager 2 took detailed photos of Jupiterrsquos moons and cloud tops in July 1979 Flying past Saturn in August 1981 Voyager 2 measured the thickness of Saturnrsquos rings and took detailed photos of many of its moons This second explorer then captured images of Uranus and Neptune before leaving our solar system
At Left The difference in technology between generations of space probes can be stunning The top two photos of Jupiter and Saturn were taken by Pioneer 11 in 1974 (Jupiter) and 1979 (Saturn) the bottom two were taken by Cassini in 2000 (Jupiter) and 2016 (Saturn) What kinds of photos await us from future generations of deep space explorers
Cassini-Huygens was the last mission to visit both worlds Launched in 1997 the mission flew past Jupiter in late 2000 and took incredibly detailed photos of its stormy atmosphere and faint rings Cassini entered into Saturnrsquos orbit on July 1 2004 The Huygens probe separated from Cassini landing on Titan to
become the first probe in the outer solar system Cassini discovered geysers on Enceladus fine details in Saturnrsquos rings many more moons and ldquomoonletsrdquo the changing oceans of Titan and seasonal changes on Saturn itself After revolutionizing our understanding of the Saturnian system Cassinirsquos mission ended with a fiery plunge into its atmosphere on September 15 2017 Whatrsquos next for the exploration of the outer worlds of our solar system While Juno is currently in orbit around Jupiter there are more missions in development to study the moons of Jupiter and Saturn Discover more about future NASA missions to the outer worlds of our solar system at nasagov
NASA Night Sky Notes
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
2
Sun Mon Tue Wed Thu Fri Sat
1 2 3 4 5 BSU
1st Friday Astronomy
see Calendar of Events
below
6 7 8 9 10 11 12 Last Quarter
Moon
Visible 45 darr
Age 2265 Days
BAS Board Meeting
700 pm via Zoom
BAS General Mtg
700 pm via Zoom
see Calendar of Events
below
13 14 15 16 17 18 19 New Moon rarr
Visible 0
Age 2933 Days
Geminid Meteor Shower
This yearrsquos
BEST meteors
20 21 22 23 24 25 26 First Quarter rarr
Moon rarr
Visible 45 uarr
Age 693 Days
Jupiter - Saturn
Conjunction
see Calendar of Events
below
Ursid Meteor Shower
early in the
morning
UFS Alert
see Calendar
of Events below
27 28 29 30 31 Cold Moon
830 pm
Visible 100
Age 1510 Days
TABLE of CONTENTS Calendar of Events 3 Currents in Space 4 NASA Night Sky Notes 6
Phil Harringtonrsquos Cosmic Challenge 7 Dave Mitskyrsquos Celestial Calendar 10 Join BAS 14
December 2020 Calendar
3
Friday December 4 Boise State Physics First Friday Astronomy
ldquoNASArsquos Lucy Mission 1 Spacecraft 7 Trojan Asteroids 12 yearsrdquo by Dr Cathy Olkin Southwest Research Inst Online Lecture begins 730 pm (MT) httpwwwastrojackcomffa-lucy-mission
If you missed this presentation you can view it and other previous lectures online at httpwwwastrojackcom
Nov 6 2020 A Practical Guide to Time Travel by Prof Barbara Ryden Dept of Astronomy The Ohio State University Oct 2 2020 The Solar System Laboratory A Testbed for Exoplanet Studies by Dr Laura Mayorga Space Telescope Science Institute
Sept 4 2020 Peering Through the Haze Titanrsquos Fascinating Atmosphere and Surface by Darci Snowden Professor of Physics Central Washington University
Aug 7 2020 Sub-Orbital Ballooning Experiments and Education by Dr Paul Verhage Treasure Valley Math amp Science Center
July 3 2020 ldquoWhat are these yellowballsrdquo How citizen scientistsrsquo curiosity led to a new catalog of star formation tracers by Prof Katie Devine College of Idaho
June 6 2020 The Antikythera Mechanism by James Evans Professor of Physics University of Puget Sound
Scheduled for Jan 1 2021 The Discovery of Neptune by Prof Brian Jackson Dept of Physics Boise State University
----------------------------------------------------------------------------------------------------------------------------- ------ Friday Dec 11 BAS General Meeting guest speaker - Dr Heidi Wu Join us for our General Meeting and hear our guest speaker Asst Prof Heidi Wu Department of Physics at Boise State University She will be speaking on ldquoWhy is our Universe Acceleratingrdquo Her research at BSU involves using ldquogalaxy clusters to probe the composition of our Universerdquo You can learn more about her on her website httpshywugithubio This will be a fun evening
----------------------------------------------------------------------------------------------------------------------------- ------ Monday Dec 21st Jupiter and Saturn Conjunction This is the first Jupiter-Saturn conjunction to be observed since the year 2000 and the closest pairing since the year 1623 The next view-worthy close-up conjunction wonrsquot be until March 2080 This year the event falls on the winter solstice with the worlds looking like a double-planet low in the SSW sky near the horizon just after sunset a mere 01 degrees apart (15 of a full moon) Jupiter will be the brighter of the two with Saturn appearing as if a 1st-magnitude star (and if we could see the Milky Way in our sky the conjunction would be next to it) Earth amp Sky has a lovely comprehensive article on this astronomical event In this issue of SkyWatcher the NASA Night Sky Notes is about the exploration history of Jupiter and Saturn
----------------------------------------------------------------------------------------------------------------------------- ------ Thursday Dec 24 Annual UFS Alert For over 100 years there have been UFS sightings very late at night on December 24th across the United States and over much of Europe People who claim to have seen the Unidentified Flying Sleigh say it appears to be something out of Victorian times but up in the sky flying over the rooftops of homes Stranger still are the reports that eight caribou appear to precede the antique vehicle as it moves through the air Observers from rural areas claim to have heard a voice with the sighting a male voice reminiscent of a happy old grandfatherrsquos deep-throated laugh Even more odd in some cases objects mysteriously appear inside peoplersquos homes though doors and windows were locked There is nothing to be concerned about though Every confirmed sighting has resulted in feelings of peace joy and goodwill to all
Calendar of Events
4
by Loretta J Cannon
SAD NEWS FOR ASTRONOMY ndash ARICEBO TELESCOPE COLLAPSE
Some of you may have been heard the 900-ton instrument platform for the Arecibo main radio telescope crashed onto the 305-meter reflector dish at 755 am local time on December 1st No one was injured as operations had been halted four months ago when a support cable snapped on August 10th at 245 am local time This first cable break created a 100-foot long gash on the edge of the reflector dish Three months later on November 6th a main cable broke on the same support tower By November 19th the decision was made to decommission the telescope And then it fell The loss of this instrument is a heavy blow to the fields of planetary science atmospheric science and both radio and radar astronomy Wersquove also lost one of only two planetary radar facilities working with NASArsquos Near-Earth Object observing program to characterize optically-detected objects
At Right intact Arecibo telescope in 2018 [credit UCFAreciboNSF]
The Arecibo Observatory is comprised of not only the now-collapsed main 305-meter radio telescope but also a much smaller 12-meter radio telescope a LIDAR facility and world-class research and visitor centers The Observatory is currently managed by the University of Central Florida (UCF) in partnership with the Universidad Ana G Meacutendez and Yang Enterprises under the US National Science Foundation (NSF) The main radio telescope had been in operation for 57 years Built over a natural sinkhole the telescope lsquoheardrsquo first light in 1963 Prof William E Gordon of Cornell University
conceived the observatory in 1958 and after it was built Cornell University managed the site from 1963 until 2011 when the contract was awarded to SRI International Then in February 2018 management was granted to the UCF-led consortium [Herersquos a funny fact the silly people who write
for Britannicacom failed to check the facts their update for the collapsed telescope reports Cornell Univ is still managing the
site oops] Until 2016 Arecibo had been the worldrsquos largest filled-aperture telescope when Chinarsquos Five-hundred meter Aperture Spherical Telescope (FAST) went online A unique feature of Arecibo was its 2 megawatt transmitter as the telescope was also designed to study the Earthrsquos ionosphere At Left Damage caused by the first cable snap [credit UCF]
Over the last five and a half decades the Arecibo observatory has been involved in not only ground-breaking but also Nobel-worthy science In the summer of 1974 radioastronomer Joseph Taylor and graduate student Russell Hulse discovered the first binary pulsar providing evidence in support of Einsteinrsquos General Theory of Relativity a discovery for which they received the 1993 Nobel Prize in Physics Also in 1974 (when Frank Drake was the observatory director) a rsquoHellorsquo message was sent into space That was (and still is) the most powerful message sent from Earth The NASA SETI listening program at Arecibo ran from 1992-93 after which time university and private institutions used Arecibo for SETI studies Also in 1992 astronomer Alex Wolszczsan discovered the first exoplanet while at Arecibo In 2016 investigators discovered the first repeating fast radio bursts millisecond radio pulses that lsquoappearrsquo extra-galactic in origin In 2017 the discovery of two pulsars that undergo lsquoa cosmic vanishing actrsquo ldquoupended the widely held view that all pulsars are orderly ticking clocks of the universerdquo As part of NASArsquos Near-Earth Object (NEO) observing program after an NEO was
Currents in Space
5
identified by an optical telescope Arecibo was able to precisely characterize it ndash size shape composition speed trajectory ndash allowing NASArsquos Planetary Defense Coordination Office time to formulate risk management plans Finally in addition to its decades of searching for SETI signals mapping pulsars finding extra-galactic radio sources pinging near-Earth asteroids and making atmospheric observations of Earth Arecibo has also been featured in the films Golden Eye (1995) and Contact (1997)
As part of the decommissioning process drones flew over the telescope evaluating the damage Because of this we have aerial footage of the collapse courtesy of the Observatory and NSF There are two videos in this footage in the first you can hear the structure crashing down while the second is like watching a close-up disaster movie scene that slowly pans back to a wide shot of the devastation It is heart-breaking to watch the structure fall knowing all that went with it At Left Collapse on December 1 2020 [credit Prof Abel Meacutendez Arecibo (ProfAbelMendez)]
Even without the main telescope Arecibo Observatory will continue as an international research facility And on the planetary defense side of the equation NASArsquos Goldstone complex (one of
the Deep Space Network sites listening to our Voyagers) is the other radar facility fully capable of characterizing an NEO detected by a network of optical telescopes
-------------------------------------------------------------------------------------------------------------------
ldquoCOSMIC PURSUITSrdquo FOR DECEMBER I highly encourage you to check out Brian Ventrudorsquos Cosmic Pursuits for December where yoursquoll find this image and more
ldquoThe waxing crescent Moon below Jupiter and Saturn after sunset on Dec 16 2020 The two planets continue to move closer to each other until Dec 21 when they lie less than 01 degree apart their closest conjunction since 1623rdquo
[image produced using SkySafari 6 Plus software httpsskysafariastronomycom]
6
Visitors to Both Jupiter and Saturn by David Prosper Have you observed Jupiter and Saturn moving closer to each other over the past few months On December 21 the two worlds will be at their closest around 15 of a full Moon apart While the two gas giants may appear close in reality they are hundreds of millions of miles apart Despite this vast distance a select few missions have visited both worlds by using a gravity assist from giant Jupiter to slingshot them towards Saturn saving time and fuel Pioneer 11 was the first mission to visit both worlds Launched in 1973 the probe flew past Jupiter in late 1974 passing just 26400 miles above its stormy clouds In 1979 it became the first spacecraft to encounter Saturn Pioneer 11 took the first up-close photos of Saturn and its satellites and made many exciting discoveries including the detections of its magnetic field and a faint ldquoFrdquo ring before departing Saturn and eventually the solar system The Voyager missions quickly followed up taking a ldquoGrand Tourrdquo of the four largest and most distant planets in our solar system Both probes were launched within two weeks of each other in 1977 Voyager 1 flew past Jupiter in March 1979 discovering Jupiterrsquos faint ring and two new moons along with active volcanoes on Iorsquos surface The probe then flew past Saturn in November 1980 discovering five new moons a new ldquoGrdquo ring mysterious ring ldquospokesrdquo and ldquoshepherd moonsrdquo shaping the rings After a brief encounter with Titan revealed evidence of complex organic chemistry and liquid on the moonrsquos frigid surface Voyager 1 was flung out of the plane of the solar system Following close behind Voyager 2 took detailed photos of Jupiterrsquos moons and cloud tops in July 1979 Flying past Saturn in August 1981 Voyager 2 measured the thickness of Saturnrsquos rings and took detailed photos of many of its moons This second explorer then captured images of Uranus and Neptune before leaving our solar system
At Left The difference in technology between generations of space probes can be stunning The top two photos of Jupiter and Saturn were taken by Pioneer 11 in 1974 (Jupiter) and 1979 (Saturn) the bottom two were taken by Cassini in 2000 (Jupiter) and 2016 (Saturn) What kinds of photos await us from future generations of deep space explorers
Cassini-Huygens was the last mission to visit both worlds Launched in 1997 the mission flew past Jupiter in late 2000 and took incredibly detailed photos of its stormy atmosphere and faint rings Cassini entered into Saturnrsquos orbit on July 1 2004 The Huygens probe separated from Cassini landing on Titan to
become the first probe in the outer solar system Cassini discovered geysers on Enceladus fine details in Saturnrsquos rings many more moons and ldquomoonletsrdquo the changing oceans of Titan and seasonal changes on Saturn itself After revolutionizing our understanding of the Saturnian system Cassinirsquos mission ended with a fiery plunge into its atmosphere on September 15 2017 Whatrsquos next for the exploration of the outer worlds of our solar system While Juno is currently in orbit around Jupiter there are more missions in development to study the moons of Jupiter and Saturn Discover more about future NASA missions to the outer worlds of our solar system at nasagov
NASA Night Sky Notes
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
3
Friday December 4 Boise State Physics First Friday Astronomy
ldquoNASArsquos Lucy Mission 1 Spacecraft 7 Trojan Asteroids 12 yearsrdquo by Dr Cathy Olkin Southwest Research Inst Online Lecture begins 730 pm (MT) httpwwwastrojackcomffa-lucy-mission
If you missed this presentation you can view it and other previous lectures online at httpwwwastrojackcom
Nov 6 2020 A Practical Guide to Time Travel by Prof Barbara Ryden Dept of Astronomy The Ohio State University Oct 2 2020 The Solar System Laboratory A Testbed for Exoplanet Studies by Dr Laura Mayorga Space Telescope Science Institute
Sept 4 2020 Peering Through the Haze Titanrsquos Fascinating Atmosphere and Surface by Darci Snowden Professor of Physics Central Washington University
Aug 7 2020 Sub-Orbital Ballooning Experiments and Education by Dr Paul Verhage Treasure Valley Math amp Science Center
July 3 2020 ldquoWhat are these yellowballsrdquo How citizen scientistsrsquo curiosity led to a new catalog of star formation tracers by Prof Katie Devine College of Idaho
June 6 2020 The Antikythera Mechanism by James Evans Professor of Physics University of Puget Sound
Scheduled for Jan 1 2021 The Discovery of Neptune by Prof Brian Jackson Dept of Physics Boise State University
----------------------------------------------------------------------------------------------------------------------------- ------ Friday Dec 11 BAS General Meeting guest speaker - Dr Heidi Wu Join us for our General Meeting and hear our guest speaker Asst Prof Heidi Wu Department of Physics at Boise State University She will be speaking on ldquoWhy is our Universe Acceleratingrdquo Her research at BSU involves using ldquogalaxy clusters to probe the composition of our Universerdquo You can learn more about her on her website httpshywugithubio This will be a fun evening
----------------------------------------------------------------------------------------------------------------------------- ------ Monday Dec 21st Jupiter and Saturn Conjunction This is the first Jupiter-Saturn conjunction to be observed since the year 2000 and the closest pairing since the year 1623 The next view-worthy close-up conjunction wonrsquot be until March 2080 This year the event falls on the winter solstice with the worlds looking like a double-planet low in the SSW sky near the horizon just after sunset a mere 01 degrees apart (15 of a full moon) Jupiter will be the brighter of the two with Saturn appearing as if a 1st-magnitude star (and if we could see the Milky Way in our sky the conjunction would be next to it) Earth amp Sky has a lovely comprehensive article on this astronomical event In this issue of SkyWatcher the NASA Night Sky Notes is about the exploration history of Jupiter and Saturn
----------------------------------------------------------------------------------------------------------------------------- ------ Thursday Dec 24 Annual UFS Alert For over 100 years there have been UFS sightings very late at night on December 24th across the United States and over much of Europe People who claim to have seen the Unidentified Flying Sleigh say it appears to be something out of Victorian times but up in the sky flying over the rooftops of homes Stranger still are the reports that eight caribou appear to precede the antique vehicle as it moves through the air Observers from rural areas claim to have heard a voice with the sighting a male voice reminiscent of a happy old grandfatherrsquos deep-throated laugh Even more odd in some cases objects mysteriously appear inside peoplersquos homes though doors and windows were locked There is nothing to be concerned about though Every confirmed sighting has resulted in feelings of peace joy and goodwill to all
Calendar of Events
4
by Loretta J Cannon
SAD NEWS FOR ASTRONOMY ndash ARICEBO TELESCOPE COLLAPSE
Some of you may have been heard the 900-ton instrument platform for the Arecibo main radio telescope crashed onto the 305-meter reflector dish at 755 am local time on December 1st No one was injured as operations had been halted four months ago when a support cable snapped on August 10th at 245 am local time This first cable break created a 100-foot long gash on the edge of the reflector dish Three months later on November 6th a main cable broke on the same support tower By November 19th the decision was made to decommission the telescope And then it fell The loss of this instrument is a heavy blow to the fields of planetary science atmospheric science and both radio and radar astronomy Wersquove also lost one of only two planetary radar facilities working with NASArsquos Near-Earth Object observing program to characterize optically-detected objects
At Right intact Arecibo telescope in 2018 [credit UCFAreciboNSF]
The Arecibo Observatory is comprised of not only the now-collapsed main 305-meter radio telescope but also a much smaller 12-meter radio telescope a LIDAR facility and world-class research and visitor centers The Observatory is currently managed by the University of Central Florida (UCF) in partnership with the Universidad Ana G Meacutendez and Yang Enterprises under the US National Science Foundation (NSF) The main radio telescope had been in operation for 57 years Built over a natural sinkhole the telescope lsquoheardrsquo first light in 1963 Prof William E Gordon of Cornell University
conceived the observatory in 1958 and after it was built Cornell University managed the site from 1963 until 2011 when the contract was awarded to SRI International Then in February 2018 management was granted to the UCF-led consortium [Herersquos a funny fact the silly people who write
for Britannicacom failed to check the facts their update for the collapsed telescope reports Cornell Univ is still managing the
site oops] Until 2016 Arecibo had been the worldrsquos largest filled-aperture telescope when Chinarsquos Five-hundred meter Aperture Spherical Telescope (FAST) went online A unique feature of Arecibo was its 2 megawatt transmitter as the telescope was also designed to study the Earthrsquos ionosphere At Left Damage caused by the first cable snap [credit UCF]
Over the last five and a half decades the Arecibo observatory has been involved in not only ground-breaking but also Nobel-worthy science In the summer of 1974 radioastronomer Joseph Taylor and graduate student Russell Hulse discovered the first binary pulsar providing evidence in support of Einsteinrsquos General Theory of Relativity a discovery for which they received the 1993 Nobel Prize in Physics Also in 1974 (when Frank Drake was the observatory director) a rsquoHellorsquo message was sent into space That was (and still is) the most powerful message sent from Earth The NASA SETI listening program at Arecibo ran from 1992-93 after which time university and private institutions used Arecibo for SETI studies Also in 1992 astronomer Alex Wolszczsan discovered the first exoplanet while at Arecibo In 2016 investigators discovered the first repeating fast radio bursts millisecond radio pulses that lsquoappearrsquo extra-galactic in origin In 2017 the discovery of two pulsars that undergo lsquoa cosmic vanishing actrsquo ldquoupended the widely held view that all pulsars are orderly ticking clocks of the universerdquo As part of NASArsquos Near-Earth Object (NEO) observing program after an NEO was
Currents in Space
5
identified by an optical telescope Arecibo was able to precisely characterize it ndash size shape composition speed trajectory ndash allowing NASArsquos Planetary Defense Coordination Office time to formulate risk management plans Finally in addition to its decades of searching for SETI signals mapping pulsars finding extra-galactic radio sources pinging near-Earth asteroids and making atmospheric observations of Earth Arecibo has also been featured in the films Golden Eye (1995) and Contact (1997)
As part of the decommissioning process drones flew over the telescope evaluating the damage Because of this we have aerial footage of the collapse courtesy of the Observatory and NSF There are two videos in this footage in the first you can hear the structure crashing down while the second is like watching a close-up disaster movie scene that slowly pans back to a wide shot of the devastation It is heart-breaking to watch the structure fall knowing all that went with it At Left Collapse on December 1 2020 [credit Prof Abel Meacutendez Arecibo (ProfAbelMendez)]
Even without the main telescope Arecibo Observatory will continue as an international research facility And on the planetary defense side of the equation NASArsquos Goldstone complex (one of
the Deep Space Network sites listening to our Voyagers) is the other radar facility fully capable of characterizing an NEO detected by a network of optical telescopes
-------------------------------------------------------------------------------------------------------------------
ldquoCOSMIC PURSUITSrdquo FOR DECEMBER I highly encourage you to check out Brian Ventrudorsquos Cosmic Pursuits for December where yoursquoll find this image and more
ldquoThe waxing crescent Moon below Jupiter and Saturn after sunset on Dec 16 2020 The two planets continue to move closer to each other until Dec 21 when they lie less than 01 degree apart their closest conjunction since 1623rdquo
[image produced using SkySafari 6 Plus software httpsskysafariastronomycom]
6
Visitors to Both Jupiter and Saturn by David Prosper Have you observed Jupiter and Saturn moving closer to each other over the past few months On December 21 the two worlds will be at their closest around 15 of a full Moon apart While the two gas giants may appear close in reality they are hundreds of millions of miles apart Despite this vast distance a select few missions have visited both worlds by using a gravity assist from giant Jupiter to slingshot them towards Saturn saving time and fuel Pioneer 11 was the first mission to visit both worlds Launched in 1973 the probe flew past Jupiter in late 1974 passing just 26400 miles above its stormy clouds In 1979 it became the first spacecraft to encounter Saturn Pioneer 11 took the first up-close photos of Saturn and its satellites and made many exciting discoveries including the detections of its magnetic field and a faint ldquoFrdquo ring before departing Saturn and eventually the solar system The Voyager missions quickly followed up taking a ldquoGrand Tourrdquo of the four largest and most distant planets in our solar system Both probes were launched within two weeks of each other in 1977 Voyager 1 flew past Jupiter in March 1979 discovering Jupiterrsquos faint ring and two new moons along with active volcanoes on Iorsquos surface The probe then flew past Saturn in November 1980 discovering five new moons a new ldquoGrdquo ring mysterious ring ldquospokesrdquo and ldquoshepherd moonsrdquo shaping the rings After a brief encounter with Titan revealed evidence of complex organic chemistry and liquid on the moonrsquos frigid surface Voyager 1 was flung out of the plane of the solar system Following close behind Voyager 2 took detailed photos of Jupiterrsquos moons and cloud tops in July 1979 Flying past Saturn in August 1981 Voyager 2 measured the thickness of Saturnrsquos rings and took detailed photos of many of its moons This second explorer then captured images of Uranus and Neptune before leaving our solar system
At Left The difference in technology between generations of space probes can be stunning The top two photos of Jupiter and Saturn were taken by Pioneer 11 in 1974 (Jupiter) and 1979 (Saturn) the bottom two were taken by Cassini in 2000 (Jupiter) and 2016 (Saturn) What kinds of photos await us from future generations of deep space explorers
Cassini-Huygens was the last mission to visit both worlds Launched in 1997 the mission flew past Jupiter in late 2000 and took incredibly detailed photos of its stormy atmosphere and faint rings Cassini entered into Saturnrsquos orbit on July 1 2004 The Huygens probe separated from Cassini landing on Titan to
become the first probe in the outer solar system Cassini discovered geysers on Enceladus fine details in Saturnrsquos rings many more moons and ldquomoonletsrdquo the changing oceans of Titan and seasonal changes on Saturn itself After revolutionizing our understanding of the Saturnian system Cassinirsquos mission ended with a fiery plunge into its atmosphere on September 15 2017 Whatrsquos next for the exploration of the outer worlds of our solar system While Juno is currently in orbit around Jupiter there are more missions in development to study the moons of Jupiter and Saturn Discover more about future NASA missions to the outer worlds of our solar system at nasagov
NASA Night Sky Notes
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
4
by Loretta J Cannon
SAD NEWS FOR ASTRONOMY ndash ARICEBO TELESCOPE COLLAPSE
Some of you may have been heard the 900-ton instrument platform for the Arecibo main radio telescope crashed onto the 305-meter reflector dish at 755 am local time on December 1st No one was injured as operations had been halted four months ago when a support cable snapped on August 10th at 245 am local time This first cable break created a 100-foot long gash on the edge of the reflector dish Three months later on November 6th a main cable broke on the same support tower By November 19th the decision was made to decommission the telescope And then it fell The loss of this instrument is a heavy blow to the fields of planetary science atmospheric science and both radio and radar astronomy Wersquove also lost one of only two planetary radar facilities working with NASArsquos Near-Earth Object observing program to characterize optically-detected objects
At Right intact Arecibo telescope in 2018 [credit UCFAreciboNSF]
The Arecibo Observatory is comprised of not only the now-collapsed main 305-meter radio telescope but also a much smaller 12-meter radio telescope a LIDAR facility and world-class research and visitor centers The Observatory is currently managed by the University of Central Florida (UCF) in partnership with the Universidad Ana G Meacutendez and Yang Enterprises under the US National Science Foundation (NSF) The main radio telescope had been in operation for 57 years Built over a natural sinkhole the telescope lsquoheardrsquo first light in 1963 Prof William E Gordon of Cornell University
conceived the observatory in 1958 and after it was built Cornell University managed the site from 1963 until 2011 when the contract was awarded to SRI International Then in February 2018 management was granted to the UCF-led consortium [Herersquos a funny fact the silly people who write
for Britannicacom failed to check the facts their update for the collapsed telescope reports Cornell Univ is still managing the
site oops] Until 2016 Arecibo had been the worldrsquos largest filled-aperture telescope when Chinarsquos Five-hundred meter Aperture Spherical Telescope (FAST) went online A unique feature of Arecibo was its 2 megawatt transmitter as the telescope was also designed to study the Earthrsquos ionosphere At Left Damage caused by the first cable snap [credit UCF]
Over the last five and a half decades the Arecibo observatory has been involved in not only ground-breaking but also Nobel-worthy science In the summer of 1974 radioastronomer Joseph Taylor and graduate student Russell Hulse discovered the first binary pulsar providing evidence in support of Einsteinrsquos General Theory of Relativity a discovery for which they received the 1993 Nobel Prize in Physics Also in 1974 (when Frank Drake was the observatory director) a rsquoHellorsquo message was sent into space That was (and still is) the most powerful message sent from Earth The NASA SETI listening program at Arecibo ran from 1992-93 after which time university and private institutions used Arecibo for SETI studies Also in 1992 astronomer Alex Wolszczsan discovered the first exoplanet while at Arecibo In 2016 investigators discovered the first repeating fast radio bursts millisecond radio pulses that lsquoappearrsquo extra-galactic in origin In 2017 the discovery of two pulsars that undergo lsquoa cosmic vanishing actrsquo ldquoupended the widely held view that all pulsars are orderly ticking clocks of the universerdquo As part of NASArsquos Near-Earth Object (NEO) observing program after an NEO was
Currents in Space
5
identified by an optical telescope Arecibo was able to precisely characterize it ndash size shape composition speed trajectory ndash allowing NASArsquos Planetary Defense Coordination Office time to formulate risk management plans Finally in addition to its decades of searching for SETI signals mapping pulsars finding extra-galactic radio sources pinging near-Earth asteroids and making atmospheric observations of Earth Arecibo has also been featured in the films Golden Eye (1995) and Contact (1997)
As part of the decommissioning process drones flew over the telescope evaluating the damage Because of this we have aerial footage of the collapse courtesy of the Observatory and NSF There are two videos in this footage in the first you can hear the structure crashing down while the second is like watching a close-up disaster movie scene that slowly pans back to a wide shot of the devastation It is heart-breaking to watch the structure fall knowing all that went with it At Left Collapse on December 1 2020 [credit Prof Abel Meacutendez Arecibo (ProfAbelMendez)]
Even without the main telescope Arecibo Observatory will continue as an international research facility And on the planetary defense side of the equation NASArsquos Goldstone complex (one of
the Deep Space Network sites listening to our Voyagers) is the other radar facility fully capable of characterizing an NEO detected by a network of optical telescopes
-------------------------------------------------------------------------------------------------------------------
ldquoCOSMIC PURSUITSrdquo FOR DECEMBER I highly encourage you to check out Brian Ventrudorsquos Cosmic Pursuits for December where yoursquoll find this image and more
ldquoThe waxing crescent Moon below Jupiter and Saturn after sunset on Dec 16 2020 The two planets continue to move closer to each other until Dec 21 when they lie less than 01 degree apart their closest conjunction since 1623rdquo
[image produced using SkySafari 6 Plus software httpsskysafariastronomycom]
6
Visitors to Both Jupiter and Saturn by David Prosper Have you observed Jupiter and Saturn moving closer to each other over the past few months On December 21 the two worlds will be at their closest around 15 of a full Moon apart While the two gas giants may appear close in reality they are hundreds of millions of miles apart Despite this vast distance a select few missions have visited both worlds by using a gravity assist from giant Jupiter to slingshot them towards Saturn saving time and fuel Pioneer 11 was the first mission to visit both worlds Launched in 1973 the probe flew past Jupiter in late 1974 passing just 26400 miles above its stormy clouds In 1979 it became the first spacecraft to encounter Saturn Pioneer 11 took the first up-close photos of Saturn and its satellites and made many exciting discoveries including the detections of its magnetic field and a faint ldquoFrdquo ring before departing Saturn and eventually the solar system The Voyager missions quickly followed up taking a ldquoGrand Tourrdquo of the four largest and most distant planets in our solar system Both probes were launched within two weeks of each other in 1977 Voyager 1 flew past Jupiter in March 1979 discovering Jupiterrsquos faint ring and two new moons along with active volcanoes on Iorsquos surface The probe then flew past Saturn in November 1980 discovering five new moons a new ldquoGrdquo ring mysterious ring ldquospokesrdquo and ldquoshepherd moonsrdquo shaping the rings After a brief encounter with Titan revealed evidence of complex organic chemistry and liquid on the moonrsquos frigid surface Voyager 1 was flung out of the plane of the solar system Following close behind Voyager 2 took detailed photos of Jupiterrsquos moons and cloud tops in July 1979 Flying past Saturn in August 1981 Voyager 2 measured the thickness of Saturnrsquos rings and took detailed photos of many of its moons This second explorer then captured images of Uranus and Neptune before leaving our solar system
At Left The difference in technology between generations of space probes can be stunning The top two photos of Jupiter and Saturn were taken by Pioneer 11 in 1974 (Jupiter) and 1979 (Saturn) the bottom two were taken by Cassini in 2000 (Jupiter) and 2016 (Saturn) What kinds of photos await us from future generations of deep space explorers
Cassini-Huygens was the last mission to visit both worlds Launched in 1997 the mission flew past Jupiter in late 2000 and took incredibly detailed photos of its stormy atmosphere and faint rings Cassini entered into Saturnrsquos orbit on July 1 2004 The Huygens probe separated from Cassini landing on Titan to
become the first probe in the outer solar system Cassini discovered geysers on Enceladus fine details in Saturnrsquos rings many more moons and ldquomoonletsrdquo the changing oceans of Titan and seasonal changes on Saturn itself After revolutionizing our understanding of the Saturnian system Cassinirsquos mission ended with a fiery plunge into its atmosphere on September 15 2017 Whatrsquos next for the exploration of the outer worlds of our solar system While Juno is currently in orbit around Jupiter there are more missions in development to study the moons of Jupiter and Saturn Discover more about future NASA missions to the outer worlds of our solar system at nasagov
NASA Night Sky Notes
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
5
identified by an optical telescope Arecibo was able to precisely characterize it ndash size shape composition speed trajectory ndash allowing NASArsquos Planetary Defense Coordination Office time to formulate risk management plans Finally in addition to its decades of searching for SETI signals mapping pulsars finding extra-galactic radio sources pinging near-Earth asteroids and making atmospheric observations of Earth Arecibo has also been featured in the films Golden Eye (1995) and Contact (1997)
As part of the decommissioning process drones flew over the telescope evaluating the damage Because of this we have aerial footage of the collapse courtesy of the Observatory and NSF There are two videos in this footage in the first you can hear the structure crashing down while the second is like watching a close-up disaster movie scene that slowly pans back to a wide shot of the devastation It is heart-breaking to watch the structure fall knowing all that went with it At Left Collapse on December 1 2020 [credit Prof Abel Meacutendez Arecibo (ProfAbelMendez)]
Even without the main telescope Arecibo Observatory will continue as an international research facility And on the planetary defense side of the equation NASArsquos Goldstone complex (one of
the Deep Space Network sites listening to our Voyagers) is the other radar facility fully capable of characterizing an NEO detected by a network of optical telescopes
-------------------------------------------------------------------------------------------------------------------
ldquoCOSMIC PURSUITSrdquo FOR DECEMBER I highly encourage you to check out Brian Ventrudorsquos Cosmic Pursuits for December where yoursquoll find this image and more
ldquoThe waxing crescent Moon below Jupiter and Saturn after sunset on Dec 16 2020 The two planets continue to move closer to each other until Dec 21 when they lie less than 01 degree apart their closest conjunction since 1623rdquo
[image produced using SkySafari 6 Plus software httpsskysafariastronomycom]
6
Visitors to Both Jupiter and Saturn by David Prosper Have you observed Jupiter and Saturn moving closer to each other over the past few months On December 21 the two worlds will be at their closest around 15 of a full Moon apart While the two gas giants may appear close in reality they are hundreds of millions of miles apart Despite this vast distance a select few missions have visited both worlds by using a gravity assist from giant Jupiter to slingshot them towards Saturn saving time and fuel Pioneer 11 was the first mission to visit both worlds Launched in 1973 the probe flew past Jupiter in late 1974 passing just 26400 miles above its stormy clouds In 1979 it became the first spacecraft to encounter Saturn Pioneer 11 took the first up-close photos of Saturn and its satellites and made many exciting discoveries including the detections of its magnetic field and a faint ldquoFrdquo ring before departing Saturn and eventually the solar system The Voyager missions quickly followed up taking a ldquoGrand Tourrdquo of the four largest and most distant planets in our solar system Both probes were launched within two weeks of each other in 1977 Voyager 1 flew past Jupiter in March 1979 discovering Jupiterrsquos faint ring and two new moons along with active volcanoes on Iorsquos surface The probe then flew past Saturn in November 1980 discovering five new moons a new ldquoGrdquo ring mysterious ring ldquospokesrdquo and ldquoshepherd moonsrdquo shaping the rings After a brief encounter with Titan revealed evidence of complex organic chemistry and liquid on the moonrsquos frigid surface Voyager 1 was flung out of the plane of the solar system Following close behind Voyager 2 took detailed photos of Jupiterrsquos moons and cloud tops in July 1979 Flying past Saturn in August 1981 Voyager 2 measured the thickness of Saturnrsquos rings and took detailed photos of many of its moons This second explorer then captured images of Uranus and Neptune before leaving our solar system
At Left The difference in technology between generations of space probes can be stunning The top two photos of Jupiter and Saturn were taken by Pioneer 11 in 1974 (Jupiter) and 1979 (Saturn) the bottom two were taken by Cassini in 2000 (Jupiter) and 2016 (Saturn) What kinds of photos await us from future generations of deep space explorers
Cassini-Huygens was the last mission to visit both worlds Launched in 1997 the mission flew past Jupiter in late 2000 and took incredibly detailed photos of its stormy atmosphere and faint rings Cassini entered into Saturnrsquos orbit on July 1 2004 The Huygens probe separated from Cassini landing on Titan to
become the first probe in the outer solar system Cassini discovered geysers on Enceladus fine details in Saturnrsquos rings many more moons and ldquomoonletsrdquo the changing oceans of Titan and seasonal changes on Saturn itself After revolutionizing our understanding of the Saturnian system Cassinirsquos mission ended with a fiery plunge into its atmosphere on September 15 2017 Whatrsquos next for the exploration of the outer worlds of our solar system While Juno is currently in orbit around Jupiter there are more missions in development to study the moons of Jupiter and Saturn Discover more about future NASA missions to the outer worlds of our solar system at nasagov
NASA Night Sky Notes
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
6
Visitors to Both Jupiter and Saturn by David Prosper Have you observed Jupiter and Saturn moving closer to each other over the past few months On December 21 the two worlds will be at their closest around 15 of a full Moon apart While the two gas giants may appear close in reality they are hundreds of millions of miles apart Despite this vast distance a select few missions have visited both worlds by using a gravity assist from giant Jupiter to slingshot them towards Saturn saving time and fuel Pioneer 11 was the first mission to visit both worlds Launched in 1973 the probe flew past Jupiter in late 1974 passing just 26400 miles above its stormy clouds In 1979 it became the first spacecraft to encounter Saturn Pioneer 11 took the first up-close photos of Saturn and its satellites and made many exciting discoveries including the detections of its magnetic field and a faint ldquoFrdquo ring before departing Saturn and eventually the solar system The Voyager missions quickly followed up taking a ldquoGrand Tourrdquo of the four largest and most distant planets in our solar system Both probes were launched within two weeks of each other in 1977 Voyager 1 flew past Jupiter in March 1979 discovering Jupiterrsquos faint ring and two new moons along with active volcanoes on Iorsquos surface The probe then flew past Saturn in November 1980 discovering five new moons a new ldquoGrdquo ring mysterious ring ldquospokesrdquo and ldquoshepherd moonsrdquo shaping the rings After a brief encounter with Titan revealed evidence of complex organic chemistry and liquid on the moonrsquos frigid surface Voyager 1 was flung out of the plane of the solar system Following close behind Voyager 2 took detailed photos of Jupiterrsquos moons and cloud tops in July 1979 Flying past Saturn in August 1981 Voyager 2 measured the thickness of Saturnrsquos rings and took detailed photos of many of its moons This second explorer then captured images of Uranus and Neptune before leaving our solar system
At Left The difference in technology between generations of space probes can be stunning The top two photos of Jupiter and Saturn were taken by Pioneer 11 in 1974 (Jupiter) and 1979 (Saturn) the bottom two were taken by Cassini in 2000 (Jupiter) and 2016 (Saturn) What kinds of photos await us from future generations of deep space explorers
Cassini-Huygens was the last mission to visit both worlds Launched in 1997 the mission flew past Jupiter in late 2000 and took incredibly detailed photos of its stormy atmosphere and faint rings Cassini entered into Saturnrsquos orbit on July 1 2004 The Huygens probe separated from Cassini landing on Titan to
become the first probe in the outer solar system Cassini discovered geysers on Enceladus fine details in Saturnrsquos rings many more moons and ldquomoonletsrdquo the changing oceans of Titan and seasonal changes on Saturn itself After revolutionizing our understanding of the Saturnian system Cassinirsquos mission ended with a fiery plunge into its atmosphere on September 15 2017 Whatrsquos next for the exploration of the outer worlds of our solar system While Juno is currently in orbit around Jupiter there are more missions in development to study the moons of Jupiter and Saturn Discover more about future NASA missions to the outer worlds of our solar system at nasagov
NASA Night Sky Notes
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
7
NGC 1360
Giant binoculars and small telescopes
Target Type RA DEC Constellation Mag Size
NGC 1360 Planetary nebula 03h 333m -25deg 522rsquo Fornax 96p 64
Many stargazers consider Fornax the Furnace to be a constellation of the deep south and therefore invisible from mid-northern latitudes While it is true that Fornax scrapes the southern horizon on early winter evenings it does so at much the same altitude as Scorpius does during the summer If you can see Scorpius from your observing site in July you can see Fornax in December Assuming its clear of course The real reason so few of us take notice of Fornax is not because of its southerly location but rather its lack of luster The constellations brightest star Alpha (α) Fornacis shines at a relatively dim magnitude 39 The two other primary stars that contribute to the constellations formal pattern Beta (β) and Nu (ν) Fornacis are both below 4th magnitude To most of us those few dim stars are not much to look at but to the inventive eye of Nicolas Louis de Lacaille they formed a furnace Lacailles furnace was not the type you would use to heat your house however To him this was Fornax Chemica a small heating unit used by the chemists of his day to heat chemicals during experiments
At Left December evening star map adapted from Star Watch by Phil Harrington
Admittedly the furnace may not look so hot to naked-eye stargazers It does however hold many amazing deep-sky sights including one of the most unusual planetary nebulae in the sky Shortly after it was discovered in 1857 by the American comet hunter Lewis Swift that nebula NGC 1360 became an object of mystery and intrigue to those trying to classify it Some suggested it was an unusual emission nebula while others felt it was a planetary nebula Even after decisive studies were conducted in the 1940s by Rudolph Minkowski at Mount Wilson Observatory in California many still found it a curiosity
Phil Harringtonrsquos Cosmic Challenge
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
8
Part of that curiosity likely stemmed from NGC 1360s odd appearance The internal structure displayed by most planetary nebulae is the result of strong swirling streams of charged particles from their embedded white dwarf progenitor stars These stellar winds hollow out the central portion of the nebula and create denser outer levels or shells NGC 1360 does not show a characteristic central void Instead it appears all mixed up as evident in the image below The October 2004 issue of the Astronomical Journal includes a paper entitled Physical Structure of Planetary Nebulae III The Large and Evolved NGC 1360 that reported on the research results conducted by Daniel Goldman and his colleagues of the Department of Astronomy University of Illinois at Urbana-Champaign Their studies found
ldquoThere exist planetary nebulae that do not possess morphological features that suggest the presence of wind-wind interactions NGC 1360 is such a planetary nebula Its surface brightness does not dip deeply at the center or rise steeply at the limb to indicate a hollow-shell structurerdquo
They concluded that the lack of a sharp internal edge to NGC 1360 is due to the absence of fast stellar winds A later study The Planetary Nebula NGC 1360 A Test Case of Magnetic Collimation and Evolution after the Fast Wind published in the March 20 2008 Astrophysical Journal by M T Garcia-Diaz and others from the Instituto de Astronomia Universidad Nacional Autonoma de Mexico concluded that the fast stellar wind from the central star [in NGC 1360] has died away at least a few thousand years ago and a back-filling process has modified its structure producing a smooth nearly featureless and elongated high excitation nebula One reason for this appearance undoubtedly has to do with the central stars Thats right stars The central star had been suspected to be binary as far back as 1977 but it took 40 years to finally prove it A study made with the Southern African Large Telescope (SALT) and published in January 2018 entitled SALT HRS discovery of a long-period double-degenerate binary in the planetary nebula NGC 1360 (Monthly Notices of the Royal Astronomical Society 473 (2) 2275) confirmed that the odd binary system consists of low-mass O-type star and a white dwarf As the study noted Around 50 short-period binary central stars (periods ~ 1 day) are
known but only four with measured orbital periods over 10 days are known The binary system in NGC 1360 shows an orbital period of 142 days Clearly these discoveries will continue to intrigue stellar astronomers just as they intrigue us if for different reasons While NGC 1360 is bright enough to be seen through large binoculars and small telescopes with relative ease pinpointing its location in the emptiness of the early winter sky can be difficult Therefore our challenge is not to understand why NGC 1360 looks like it does Our challenge is to find this unusual egg-shaped cloud in the first place Of course one way to overcome this challenge is simply to use a Go-To telescope Punch in NGC 1360 and youre there without any fuss or muss But what challenge is there in that Therefore I challenge you to find NGC 1360 without any aid whatsoever save for your finderscope and a star atlas that is a star atlas other than the second edition of Sky Atlas 20000 NGC 1360 was omitted from chart 18 where it should be plotted But dont worry well find it together I prefer to start at Lepus the Hare just south of mighty Orion Extend a line from Delta (δ) to Epsilon (ε) Leporis and follow it toward the west for about 17deg Through your finderscope or binoculars look for a trapezoidal pattern formed from Tau-6 (τ6) Tau-7 (τ7) Tau-8 (τ8) and Tau-9 (τ9) Eridani Once there extend a line from Tau-9 through Tau-8 continuing for about 4deg westward to a close-set pair of 6th-magnitude stars SAO 168612 and SAO 168648 NGC 1360 lies just south of the halfway point between those two stars In fact all three may just squeeze into a low-power field
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
9
Keep in mind that you are not looking for a small disk of light but rather a large glowing cloud To put things in perspective the largest brightest planetary nebula north of the celestial equator is M27 the Dumbbell Nebula in Vulpecula M27 shines at magnitude 74 and measures 8x6 By contrast NGC 1360 spans 9x5 nearly identical in apparent size At 9th magnitude however it is also four times fainter Through my 4-inch refractor NGC 1360 looks like an unusually symmetrical oval cloud of faintly greenish light resembling a cosmic egg -- hence its nickname the Robins Egg Nebula The central star shining at 11th magnitude is just visible in this aperture but is quite prominent in larger instruments Its clear in my 10-inch (25cm) Newtonian At first glance the cloud will look perfectly uniform Take a closer look however and a very subtle almost spiral-like structure becomes evident A narrowband filter helps to bring this out but unless the eye is trained to spot delicate details -- a talent only gained by years of experience -- then this will probably pass undetected
At Right Finder chart adapted from Cosmic Challenge The Ultimate Observing List for Amateurs by
Phil Harrington
At Left NGC 1360 as seen through the authors 10-inch (25cm) reflector
Good luck And be sure to post your results in this columnrsquos online discussion forum (Phil Harringtonrsquos December cosmic challenge forum) Have a favorite challenge object of your own Id love to hear about it Contact me through my web site or post to this months discussion forum Until next month remember that half of the fun is the thrill of the chase Game on
About the Author Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy including Cosmic Challenge The Ultimate Observing List for Amateurs Phil Harringtons Cosmic Challenge copyright 2020 by Philip S Harrington All rights reserved No reproduction in whole or in part beyond single copies for use by an individual is allowed without written permission of the copyright holder Permission for use in this newsletter has been granted
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
10
All times unless otherwise noted are UT (subtract 7 hours and when appropriate 1 calendar day for MDT)
121 The Moon is at the ascending node (longitude 799 degrees) at 800 122 Mars is at the ascending node through the ecliptic plane at 300 the Moon is 02 degrees north of the bright open cluster M35 in Gemini at 800 123 The Moon is at its northernmost declination of the year (+248 degrees) at 100 the Moon is 74 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 2100 124 The earliest end of evening twilight at 40 degrees north takes place today the Moon is 37 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 200 125 The Moon is 26 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 400 Mercury is at the descending node through the ecliptic plane at 1800 126 The Moon is 45 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 2000 127 The earliest sunset at latitude 40 degrees north occurs today asteroid 16 Psyche (magnitude +95) is at opposition in Taurus at 2000 the Moon is 05 degrees north of asteroid 4 Vesta with an occultation taking place in Micronesia the northern Philippines Japan most of China most of Russia and most of eastern and northern Europe at 2200 128 Last Quarter Moon occurs at 037 Mercury is 43 degrees north-northeast of the first magnitude star Antares (Alpha Scorpii) at 1100 the Curtiss Cross an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart is predicted to be visible at 1632 1212 The Moon is at perigee subtending 33 02 from a distance of 361773 kilometers (224795 miles) at 2042 the Moon is 08 degrees north of Venus with an occultation taking place in western North America Alaska Hawaii and far eastern Russia at 2100 1214 The peak of the Geminid meteor shower (a zenithal hourly rate of 100 to 120 per hour) occurs at 100 the Moon is at the descending node (longitude 2600 degrees) at 1100 the Moon is 10 degrees north-northeast of Mercury at 1200 a total solar eclipse visible from the South Pacific southern South America Antarctica the South Atlantic and southwestern Africa begins at 1433 UT1 and ends at 1754 UT1 New Moon (lunation 1212) occurs at 1616 1215 The Moon is at its southernmost declination for the year (-249 degrees) at 2200 1216 Mercury is at aphelion (04667 astronomical units from the Sun) at 300 1217 The Moon is 29 degrees south of Jupiter at 600 the Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees at 600 the Moon is 30 degrees southeast of Saturn at 700 1218 The Sun enters the constellation of Sagittarius (ecliptic longitude 2666 degrees) at 200 1220 Mercury is at superior conjunction with the Sun (1447 astronomical units from the Earth latitude -45 degrees) at 300 1221 The Moon is 42 degrees southeast of Neptune at 000 the Sun is at a longitude of 270 degrees at 1002 the northern hemisphere winter solstice occurs at 1002 Jupiter is 01 degrees south of Saturn at 1400 First Quarter Moon occurs at 2341 1222 The Lunar X (Purbach or Werner Cross) an X-shaped illumination effect involving various rims and ridges between the craters La Caille Blanchinus and Purbach is predicted to be fully formed at 433 the peak of the Ursid meteor shower (a zenithal hourly rate of 5 to 10 per hour) occurs at 900 1223 Venus is 56 degrees north of Antares at 2100 1224 The Moon is 51 degrees southeast of Mars at 000 Mercury is at its southernmost declination (-251 degrees) at 700 the Moon is at apogee subtending 29 30 from a distance of 405011 kilometers (251663 miles) at 1631 the equation of time is equal to zero at 2200 1225 The Moon is 32 degrees southeast of Uranus at 200 1227 The Moon is 58 degrees southeast of the Pleiades at 200 the Moon is 46 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 2000 1228 The Moon is at the ascending node (longitude 800 degrees) at 1500 1229 The Moon is 02 degrees north of M35 at 1500 1230 Full Moon (known as the Before Yule Cold Long Nights and Oak Moon) occurs at 328 1231 The Moon is 74 degrees south of Castor at 300 the Moon is 38 degrees south of Pollux at 800
Happy Birthdays in December [I added to Daversquos list as it was a tad short -your Editor]
Dec 7th Gerard Kuiper (1905-1973) Dec 11th Annie Jump Cannon (1863-1941) Dec 14th Tycho Brahe (1546-1601) Dec 27th Johannes Kepler (1571-1630) Dec 16th Edward Emerson Barnard (1857-1923) Dec 28th Arthur Eddington (1882-1944)
Dave Mitskyrsquos Celestial Calendar
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
11
On this date in history
Dec 3 1905 The Jovian satellite Himalia was discovered by Charles Perrine Dec 5 1751 Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) Dec 15 1791 Caroline Herschel discovered Comet C1791 X1 (Herschel) Dec 15 1966 Audouin Dolfus discovered the Saturnian satellite Janus Dec 18 1966 The Saturnian satellite Epimetheus was discovered by Richard Walker Dec 19 1783 William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans Dec 21 1788 Caroline Herschel discovered Comet 35PHerschel-Rigoliet Dec 23 1672 Giovanni Cassini discovered the Saturnian satellite Rhea Dec 31 1774 The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode
The Sun the Moon amp the Planets
The Sun is located in Scorpius on December 1st Sol enters Sagittarius on December 18th Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st It is the shortest day of the year (9 hours and 20 minutes) at latitude 40 degrees north A total solar eclipse occurs in the southern hemisphere on December 14th Itrsquos the 23rd eclipse of Saros 142 Greatest eclipse takes place in southern Argentina at 161329 UT1 and has a duration of 2 minutes 14 seconds For more on this event consult httpwwweclipsewilSE2020JDec14T or pages 48 and 49 of the December 2020 issue of Sky amp Telescope The Moon is 156 days old is illuminated 998 subtends 301 arc minutes and is located in Taurus on December 1st at 000 UT Due to the position of the ecliptic the Moon reaches its highest point in the sky for the year in December It attains its greatest northern declination for the month on December 3rd (+248 degrees) and December 30th (+248 degrees) and greatest southern declination (-249 degrees) on December 16th Longitudinal libration is at a maximum of +65 degrees on December 19th Itrsquos at a minimum of -63 degrees on December 6th Latitudinal libration is at a maximum of +69 degrees on December 21st and a minimum of -68 degrees on December 8th Favorable librations for the following lunar features occur on the indicated dates Crater Rydberg on December 6th Crater Andersson on December 8th Crater Vashakidze on December 18th and Crater Compton on December 20th New Moon occurs on December 14th The Moon Jupiter and Saturn lie within a circle with a diameter of 30 degrees on December 17th The Moon is at perigee (a distance of 5672 Earth-radii) on December 12th and at apogee (a distance of 6350 Earth-radii) on December 24th The Moon occults asteroid 4 Vesta on December 7th and Venus on December 12th from certain parts of the world Mercury heads sunward and is not visible after early December Its at aphelion on December 16th The speediest planet achieves superior conjunction on December 20th Venus rises less than 90 minutes before the Sun by the end of the month The separation between the planet and the Sun is 20 degrees on December 31st A waning crescent Moon passes less than a degree north of Venus on December 12th A daytime occultation of the planet that is discussed on page 50 of the December 2020 issue of Sky amp Telescope takes place in some locations Venus passes just 10 arc minutes north of the third-magnitude binary star Graffias (Beta Scorpii) on the morning of December 18th The brightest planet enters Ophiuchus on December 22nd and lies 56 degrees north of Antares on the morning of December 23rd During December Mars decreases in brightness from magnitude -11 to magnitude -03 in angular size from 146 arc seconds to 105 arc seconds and in illumination from 92 to 89 It culminates around 900 pm local time on December 1st and an hour earlier on December 31st The Red Planet is at its ascending node on December 1st crossing
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
12
from south to north of the ecliptic At 1000 pm EST Valles Marineris and the volcanoes of the Tharsis Ridge are well placed during the first part of the month Followed by Sinus Sabaeus Syrtis Major and the Hellas basin during the middle of December At months end Mare Cimmerium is centered on the Martian disk The waxing gibbous Moon passes 51 degrees southeast of Mars on the evening of December 23rd Jupiter and Saturn are 21 degrees apart as December begins and lie within one degree of one another from December 12th through December 29th During the first week of December the two planets set by 830 pm local time A waxing crescent Moon passes three degrees south of Jupiter and Saturn on the evening of December 16th On December 21st the two gas giants are separated by just six arc minutes less 45 minutes after sunset and are positioned about 14 degrees above the southwestern horizon some 30 degrees east of the Sun On that date Jupiter shines at magnitude -20 and subtends 333 arc seconds Saturns brightness is magnitude +06 its disk has an apparent diameter of 154 arc seconds and its rings span some 35 arc seconds This is the first conjunction of the two planets since 2000 and the closest conjunction since 1623 The last observable conjunction in which Jupiter and Saturn were closer occurred in 1226 During the conjunction Ganymede will transit Jupiter Saturns satellites Enceladus Tethys Dione and Titan will be to the west of the planet and Rhea and Mimas to the east For additional information on this Great Conjunction see httpsearthskyorgion-dec-21-2020 and httpsearthskyorgnified-dec-2020 and httpswwwtimeanddeat-conjunction Uranus lies a few degrees southeast of the sixth-magnitude star 19 Arietis in southern Aries and transits the meridian in the early evening Uranus lies five degrees northwest of the waxing gibbous Moon on December 24th Visit httpwwwnakedeyepcomuranushtm or consult page 51 of the October 2020 issue of Sky amp Telescope October for finder charts Neptune is located about three quarters of a degree northeast of the fourth-magnitude star Phi Aquarii during the early part of the month As December ends Neptune lies one degree from the star The waxing crescent Moon passes four degrees south of Neptune on 20th Neptune culminates during evening twilight and sets before midnight by the middle of the month Pluto will not be readily visible again until next year During the evenings Mars can be found in the southeast Jupiter and Saturn in the southwest Uranus in the east and Neptune in the south Mars and Uranus are in the west at midnight In the morning Mercury is located in the east and Venus in the southeast A very thin crescent Moon Mercury Venus and Spica form a trapezoid in the east-southeast on the morning of November 13th For more on the planets and how to locate them browse Naked Planets Information on passes of the ISS the USAFrsquos X-37B the HST Starlink and other satellites can be found at Heavens Above ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
The periodic comet 88PHowell shines at approximately tenth magnitude as it heads northeastward through Capricornus this month The comet passes about four degrees north of the seventh-magnitude globular cluster M30 on December 18th and approximately one degree southeast of Deneb Algedi (Delta Capricorni) on December 21st For more information on comets visible this month browse the Comet Chasing site A historical list of
the closest cometary approaches to Earth is posted on Cometography ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Asteroid 1 Ceres heads northeastward through Aquarius during December passing close to the eleventh-magnitude globular cluster NGC 7492 at the end of the month Asteroids brighter than magnitude +110 reaching opposition this month include 16 Psyche (magnitude +95) on December 7th 79 Eurynome (magnitude +99) on December 11th 13 Egeria (magnitude +100) on December 20th 39 Laetitia (magnitude +99) on December 21st 52 Europa (magnitude +102) on December 28th and 356
Liguria (magnitude +109) on December 31st Information on asteroid occultations taking place this month is available at ----------------------------------------------------------------------------------------------------------------------------- ----------------------------------
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
13
The peak of Geminid meteor shower occurs on the morning of December 14th and is not adversely affected by moonlight The Geminids which are associated with the Palladian asteroid or possible cometary nucleus 3200 Phaethon have become the most reliable meteor shower of the year Geminid meteors appear to originate from a radiant thatrsquos just northwest of Castor That radiant lies almost at the zenith at 200 am local time Geminid meteors travel at a relatively slow speed of 35 kilometers per
second (22 miles per second) An article on this yearrsquos Geminids can be found on pages 14 through 19 of the December 2020 issue of Sky amp Telescope The Ursids a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour peak on the morning of December 23rd and are somewhat affected by the First Quarter Moon The radiant is located close to Kochab (Beta Ursa Minoris) some 15 degrees from the north celestial pole See Earth amp Sky - meteor shower for additional information on the Geminids and page 49 of the December 2020 issue of Sky amp Telescope see Earth amp Sky for more on the Ursids
----------------------------------------------------------------------------------------------------------------------------- ---------------------
You are welcome to access the Cloudy Nights site for many more details from Dave Mitsky
httpswwwcloudynightscomtopic742794-december-2020-celestial-calendar
______________________________________________________________________________________________ Dear Readers Donrsquot forget the Sky amp Telescope site On their main page you will find their ldquoThis Weekrsquos Sky at a Glancerdquo feature and a Sky Tour podcast for December A feature story for December is about the tragedy at Arecibo The article by Monica Young is worth reading
ldquoThe Arecibo telescope in Puerto Rico has collapsed less than two weeks after officials announced it was too dangerous to attempt repairsrdquo httpsskyandtelescopeorgastronomy-newsthe-arecibo-telescope-has-collapsed
The cover story is on the Geminid meteor shower 2020rsquos best so far And you can read about the Caldwell Catalog which turns 25 this year An article on lsquoMeasuring the Starsrsquo enlists the help of citizen scientists I apologize that the Robots of Mars saga isnrsquot in this issue The Arecibo incident has taken up all my research time Wersquoll pick back up in January with our exploration of Mars The January Physics First Friday will be on New Yearrsquos Day and feature Prof Jackson speaking about my very favorite planet Neptune ndash because itrsquos blue Please please continue to Stay Safe
Loretta
The End
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society
14
Join the Boise Astronomical Society ndash Membership has its privileges
link httpswwwboiseastroorg
Hello and welcome to our club We hope you enjoy our newsletter from current news and celestial events to a cosmic challenge and a bit of space history We meet on the 2nd Friday of each month in rooms at the Anser Charter School at 202 E 42nd St Garden City Our meetings feature an interesting program or presentation and the opportunity to spend time with other astronomy enthusiasts A star party is a gathering of amateur astronomers for the purpose of observing the sky Observing the night sky is always an exciting journey but having others to share the experience with makes it even better We typically have two Star Parties each month around the New Moon refer to the calendar on page 2 of this newsletter or join our online Group (see below) for scheduled dates We usually meet up at Dedication Point which is on Swan Falls Road about 16 miles south of Kuna During the summer months we move to a dark sky site at Granite Creek near Idaho City These events are free and you donrsquot have to bring your own telescope Those who bring a telescope are more than happy to share views Star Parties may be planned around a specific celestial event or just on a clear night Either way observing together gives everyone an opportunity share knowledge meet new people and gain experience in stargazing that otherwise may not have been possible How to Join the Boise Astronomical Society Annual dues are $25 per Household for the calendar year running from January 1 to December 31 Click here to print the membership application form httpswwwboiseastroorguploads1220122041477new_member_application_2018pdf
This includes all family members living at the same address Mail your application and dues to us at (and please make checks payable to) Boise Astronomical Society PO Box 7002 Boise Idaho 83707 Membership entitles you to attend all BAS Star Parties educational outreach programs and membershipguest speaker meetings Your literary contributions are welcomed and encouraged Owning a telescope is NOT a requirement of joining the club Membership also includes but is not limited to
1 Membership in the Astronomical League 2 Discounts on subscriptions to Astronomy and Sky amp Telescope magazines 3 Volunteer star party opportunities 4 Camping and star party opportunities 5 First opportunity at Idaho State Parks (ISP) campsite reservations 6 Field trips to area planetariums
Join us on Groupsio We encourage you join our online Group as this is how we communicate between our monthly meetings Itrsquos easy and itrsquos
free To start use this link to create an account httpsgroupsioregister Of the (3) account-creation methods shown
we recommend that you enter your current email address and create a password this will ensure that yoursquoll get real-time
lsquoGoNo-Gorsquo notices for Star Parties The link to our group is httpsgroupsiogBoiseAstro Please keep all postings on
BAS-related topics Please ensure all conversations follow civil discourse and are related to astronomy You are also most welcome to join our Facebook group whether you are a member or not Please keep conversations and postings (including sales) to a civil discourse and be related to astronomy Also we are now using Twitter although sparingly
Boise Astronomical Society