stargazing 101 evaluation and “probing the depths and comets, meteors and auroras” chapters 6...

Stargazing 101Stargazing 101Evaluation andEvaluation and

““Probing the Depths and Probing the Depths and

Comets, Meteors and Auroras”Comets, Meteors and Auroras”Chapters 6 & 10Chapters 6 & 10

April 20, 2010April 20, 2010

Last ClassLast Class

• Evaluations• Blue sheet – for me• White sheet – for the mini-course Office

• Office of Special Programs and Continuing Education

• Assignments1. “Stargazing Log”2. “Phases of the Moon” assignment3. One-page typed reflection paper on what you learned

at the Boonshoft Planetarium4. One-page typed reflection paper on the most

interesting, unusual, or surprising thing that you observed or learned during the course.

Chapter 6Chapter 6

Probing the DepthsProbing the Depths

Deep-sky ObjectsDeep-sky Objects • Deep-sky objects – objects beyond

our solar system • Most objects you can see with your naked

eye are within our Milky Way Galaxy• “What is the one naked-eye exception?”

• Stars will always be nothing more than a point of light, “no matter how large the instrument or what magnification is used to observe a star.” (NightWatch, p. 84)

Deep-sky ObjectsDeep-sky Objects

• Light-year = the distance that light travels in a year at a constant velocity• 299,792 kilometers per second

(186,282.397 miles per second) • Ex. Betelgeuse (in Orion) is

427.47 light years from Earth, which means the light we see tonight left Betelgeuse 427.47 years ago.

• Ex. Sirius is 8.7 light years away

http://antwrp.gsfc.nasa.gov/

Double StarsDouble Stars• Hundreds of double stars can be observed

with naked-eyes and binoculars• Thousands with telescopes

• Binary systems – a pair of gravitationally associated stars

• Optical doubles – a chance alignment of stars • One is usually much closer to us than the other• NightWatch, pages 84-85

Double starsDouble stars

• Double Double in constellation Lyra• Binary double – all part of a single stellar system

www.weasner.com

Double StarsDouble Stars• Albireo – Double stars (optical) in the constellation

Cygnus, the Swan (summer and autumn)• The larger star is orange and smaller star is blue

http://zimmer.csufresno.eduwww.jb.man.ac.uk

Double StarsDouble Stars• Mizar and Alcor – are double stars in the handle

of the Big Dipper (optical)• Second stars from the end of the handle• With naked eye or binoculars

www.astropix.com

Double StarsDouble Stars

• Mizar and Alcor • Mizar itself is a double

star (binary)• Alcor• Mizar

• The Meade telescope at the UFO can separate the two stars of Mizar

www.perezmedia.net

Open Star ClustersOpen Star Clusters• Groups of a few dozen to thousands of

stars “kept in huddle together by their mutual gravity.” (p. 87)

• “At least 20 open star clusters are easy targets for binoculars…” (p. 87-88)

• NightWatch, pages 87-90

Open Star ClustersOpen Star Clusters• Messier Objects

• Charles Messier (“mess-yáy” or “me-sE-Á”)

• French astronomer (1730-1817)• Discovered and catalogued a

number of objects – star clusters, nebulae and galaxies

• 110 objects, designated “M” plus a number (ex. M44)

M7: http://apod.nasa.com

M6: http://apod.nasa.com

Open Star ClustersOpen Star Clusters

• New General Catalogue (NGC)• Sir William Herschel• German-born British astronomer (1738-1822) • Catalogued many galaxies and other space

objects, including Messier Objects• Many galaxies, star clusters, etc. now have

more than one name/designation• Herschel also discovered Uranus

Open Star ClustersOpen Star Clusters

• The Big Dipper Cluster• All but two of the stars

are part of a star cluster• Alkaid and Dubhe

• The other five stars are all related

• “Believed to be born in the same region of space about 200 million years ago.” (NightWatch, p.88)

Night Sky Magazine, March/April 2005

Ursa MajorUrsa Major

Night Sky Magazine, March/April 2005 www.gillatt.org

The entire constellation of which the Big Dipper is a part

Open Star ClustersOpen Star Clusters• The Pleiades (M45)

• Just under 400 light-years away• Often mistaken for the Little Dipper • Sometimes called the Seven Sisters• Some people can see 6-11 stars with naked eye• Beautiful in binoculars

• With a telescope, a hundred + stars can be seen

• “The approximately 400 stars in this cluster were all born about 20 million years ago.” (NightWatch, p. 88)

The PleiadesThe Pleiades

www.apod.nasa.gov

Open Star ClustersOpen Star Clusters• The Hyades

• In the constellation Taurus, the Bull• Just to the right of Aldebaran

The Hyades and the PleiadesThe Hyades and the Pleiades

Aldebaran

The Pleiades

www.starryskies.com

NebulasNebulas• Vast clouds of gas and dust around the

galaxies• A galaxy’s maternity ward

• Where new stars are born

• Bright stars sometimes light up the gases and dust for spectacular views with telescopes• NightWatch, pages 90-92

NebulasNebulas• Orion Nebula – in

Orion’s sword• Visible to the naked

eye – looks like an out-of-focus star

• Telescopes – reveal individual stars

• The best-known and brightest nebula• Nearest bright nebula• About 1,400 light

years away

www.oobleck.ifa.hawaii.edu

NebulasNebulas• Orion Nebula – in Orion’s

sword• Trapezium – four stars at center

• http://stardate.org (January 19, 2004)

• Top photo – what you might see in a telescope – looks black and white

• Bottom photo – long exposure astrophotography, reveals colors that our eyes are not sensitive to in night vision.

NightWatch, p. 95, 85

Averted VisionAverted Vision• Used when observing any low-light object• “The concept of averted vision is to concentrate

on the celestial object without looking directly at it. With the object of interest centered in the eyepiece field, direct your gaze toward the field’s edge.• It works because the eye’s visual receptors away from

the central axis of vision are more sensitive to dim light.” (NightWatch, p. 92)

• Central receptors (cones) are mostly color vision• Remember cones and rods in the retina of your eye

Globular Star ClustersGlobular Star Clusters• Look like fuzzy stars with

naked eye and binoculars• In telescopes they appear as

concentrated balls of light gradually fading off at the edge

• Cluster in Hercules (M13) • Cluster in Sagittarius (M22)

• Both are easy targets with binoculars

• Both have up to two million stars

The Cluster in Hercules

as seen using an 8-inch

telescope

The Cluster in Hercules

as seen using an 15-inch telescope

NightWatch, p. 92

Using Deep-Sky Using Deep-Sky ChartsCharts

• Excellent charts on pages 97-119 in text• Winter (#15-19) and Spring charts (#1-5)

• BlackBlack = Names: stars and constellations; deep sky objects

• BlueBlue = Observing information: type or class of object; magnitude; double- and multiple-star data; general appearance; instrumentation needed

• RedRed = Descriptive astrophysical information: distance; actual size; luminosity; classification

All year; best late winter

through summer NightWatch, p. 100

Overhead in winter

In the east in autumnOverhead in winter

Chart 15

Northeast in springOverhead in summerNorthwest in autumn NightWatch, p. 109

CenterOf theMilkyWay

Seen near southern horizon mid- to late-summer

NightWatch, p. 107

Chapter 10Chapter 10

Comets, Meteors Comets, Meteors

and Aurorasand Auroras

John Chumack: Comet Bradfield, May 2004, Yellow Springs, OH Galacticimages.com

CometsComets

CometsComets

• “Comets are essentially flying mountains of ice left over from the formation of the giant planets Uranus and Neptune.” (NightWatch, p. 156)• In orbits beyond the orbits of

Neptune and Pluto• They orbit the Sun in large

elliptical orbits that sometimes take centuries or millennium to make one loop.

NightWatch, p. 159

CometsComets

• “As they near the Sun, the cometary ice begins to be vaporized by sunlight. In the vacuum of space, the vapors create a huge cloud of gas and dust that is many times the size of Earth.” (NightWatch, p. 156)

NightWatch, p. 157

CometsComets• The most recent

easily visible comet was Hale-Bopp, which came closest to the Earth in late March and early April 1997

• Comets are named after the first two persons who discovered them and report them.

NightWatch, p. 157

MeteorsMeteors• We call them shooting stars or

falling stars but, “meteors have nothing to do with stars. They are tiny bits of space debris so small that thousands could fit in your hand.” (NightWatch, p. 160)

• They burn up as they enter the Earth’s atmosphere at very high speeds

NightWatch p. 161

MeteorsMeteors

• Meteor = the bright streak of light seen when a small bit of space debris burns up in the Earth’s atmosphere.

• Meteoroid = a small chunk of matter in space that could become a meteor.

• Meteorite = a piece of debris that survives the descent through the Earth’s atmosphere and reaches the surface. • NightWatch, p. 160

MeteorsMeteors• On the average night you can see 3-4 meteors an

hour.• Best time to see the most meteors is between 1:00 am

and dawn• When the Earth is rotated “face first” into the shower

• The meteors are like bugs hitting the windshield of a car

• Bugs don’t splatter on the side and rear windows

• Author suggests using padded, reclining lawn chairs and blankets• Binoculars and telescopes are useless – you want to

see as much of the sky as you can.

Meteor ShowersMeteor Showers

• Annual meteor showers occur when left over debris from comets intersect our orbit around the Sun.

NightWatch, p. 160

Meteor ShowersMeteor Showers

• http://www.stardate.org (April 20, 2010 – “Lyrid Meteors”)

NIghtWatch, p. 161

AurorasAuroras November 7, 2004

AurorasAuroras Midnight, November 7, 2004Over downtown Dayton

AurorasAuroras John Chumack, November 7, 2004With Big Dipper

AurorasAuroras

• Aurora Borealis or northern lights. • Auroras are caused by energetic particles blasted in

the Earth’s direction by eruptions on the Sun. • The particles are deflected by the Earth’s magnetic fields and

enter the Earth’s atmosphere over the magnetic poles• The particles stimulate gases in the upper atmosphere.

• When stimulated:• Oxygen emits a greenish white light or red hue • Nitrogen produces a bluish tint.

• http://video.google.com/videoplay?docid=2631078790090750578&ei=O2PnSsqMI5TwlQfV1pEq&q=aurora+borealis&hl=en#

Looking ahead to the Looking ahead to the Spring and Summer Spring and Summer

SkiesSkies

Spring Spring SkiesSkies

• Big Dipper• Polaris in the Little

Dipper• Arcturus in Boötes,

the Herdsman• Spica in Virgo, the

Virgin• Corvus, the Crow• Regulus in Leo, the

Lion

Using Big Dipper as GuideUsing Big Dipper as Guide

Arc to Arcturus and spike to Spicahttp://my.execpc.com

Corvus

Regulus, Leo, the Lion

Summer Summer SkiesSkies

• Summer Triangle• Vega in Lyra, the Lyre• Deneb in Cygnus, the

Swan • Altair in Aquila, the

Eagle

• Northern Cross• Cygnus, the Swan

• Delphinus, the Dolphin

• Draco, the Dragon

NightWatch, p. 51

Summer Summer SkiesSkies

• Arcturus to Vega,• Corona Borealis,

the Northern Crown

• Hercules, the Strongman

• Saggitarius, the Archer

• Antares, in Scorpius, the Scopion

• Libra, the Scales NightWatch, p. 51

Summer TriangleSummer Triangle

• Vega – Lyra, the harp

• Deneb – Cygnus, the Swan

• Altair – Aquila the Eagle

• Note: Delphinus, the Dolphin

http://vortex.accuweather.com

Northern CrossNorthern Cross

http://cdn-write.demandstudios.com

Using Big Dipper as GuideUsing Big Dipper as Guide

Draco, the dragonhttp://my.execpc.com

Arcturus to Arcturus to VegaVega

• 1/3 of the way points to Corona Borealis• The Northern Crown

• 1/3 more, points to the keystone of Hercules• M13 is the Hercules

Star Cluster• Visible with binoculars

• 1/3 more, points to Vega

http://media.skyandtelescope.com

Information on Information on ConstellationsConstellations

• Quick Constellation Guide• http://astronomyspace.suite101.com/article.cfm/quick_constellation_guide

• The Stellar Guide• http://www.botproductions.com/stellar/index.html

• Timeless Myths• http://www.timelessmyths.com/classical/stars.html

• About.com: Space/Astronomy (constellation pictures)• http://space.about.com/od/starsplanetsgalaxies/ig/Constellations-Pictures/

Good luck

and good stargazing