nasa journal of the amateur astronomers association of new ... · universe. gott, a theorist and...
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Journal of the Amateur Astronomers Association of New York
April 2016 Volume 65 Number 4; ISSN 0146-7662
AAA Brings its Starfestivities to the Bronx
By Michael David O’Gara
On Mar 19,
about 150 New
Yorkers tiptoed
through the tomb-
stones of the
Woodlawn Ceme-
tery in the Bronx
with hopes of see-
ing the splendors
of a springtime
sky at AAA’s
annual Spring
Starfest. The
evening turned out
to be cloudy and overcast, and only the Moon was visible
throughout the night, but the public had a spectacular time
talking to and observing with the AAA.
For this year’s Spring Starfest, AAA’s Surayah White
and John Benfatti coordinated all observers, volunteers, raffle
prizes, and goody bags for attendees. Club members gener-
ously brought nearly 20 telescopes for the event. AAA’s Jo-
seph Martinez presented a Solar System talk about the planet
Jupiter and entertained the crowd with his own Mars Rover
mini-car. Later in the evening, Tele Vue Optics Founder Al
Nagler gave a presentation on his personal history as an as-
tronomer and his
work with the
NASA astronaut
training team during
one of the Apollo
missions.
Mr. Nagler also
presented a new
product he designed
to enable any cell
phone to be mated to
his Delos and Delite
eyepieces. AAA’s
Sam Hahn offered
THIS MONTH: AAA’s Observing Season Begins! Plus AAA Lecture on Apr 1 and NEAF Apr 9/10.
AAA SPRING STARFEST
Untangling the Cosmic Web
By Bart Erbach
Don’t underestimate the power
of a high school science project.
One such project helped J. Richard
Gott untangle the mysteries of the
universe. Gott, a theorist and cosmol-
ogist, spoke on Mar 11 at the Ameri-
can Museum of Natural History’s
Hayden Planetarium as part of its
Frontiers Lecture Series, describing
his latest book, The Cosmic Web:
Mysterious Architecture of the Uni-
verse. A brilliant storyteller, Gott
took his audience time-travelling across the many theories
throughout history on the structure of the universe.
“He is one of the most innovative thinkers that exists,”
introduced Planetarium Director Neil DeGrasse Tyson, who
has co-authored many books with Gott and co-taught with
him at Princeton University’s Department of Astrophysics.
“There’s nothing that anybody in our field does that he
doesn't think about in some new or unusual way,” said Tyson.
“That means that sometimes it leads nowhere, but sometimes
it leads to new insights and new discoveries that no one else
could have come up with — because they didn't think to think
about it in that way.”
Gott’s lecture set out to answer one of the biggest ques-
tions of all time: “How is the stuff of the universe put togeth-
er?” With traces of his native Kentucky drawl and a disarm-
ing sense of humor, Gott began, “This is a story about a gen-
eration of astronomers who tackled that question, the Cold
War, and my high school science project.”
Holding the rapt attention of his audience, Gott used
charts, geometrical drawings, and 3-D models to explain how
various theories of the universe have developed over time. To
illustrate the notion that the universe is contracting, a far less
popular theory since the discovery of dark energy, he used a
football. He demonstrated the universe expanding from the
Big Bang at one end and then collapsing at the other, “to end
with the Big Crunch. You don't want to be there.”
Gott then took us back to visit with the pioneers of extra-
AMNH Frontiers Lecture (cont’d on Page 3) 2016 Spring Starfest (cont’d on Page 3)
AMNH FRONTIERS LECTURE
NASA
A year in space can drive you bananas! NASA’s Scott Kelly returned last month
from his historic ISS mission, but it wasn’t all work. In a Feb video, he dressed as a gorilla and chased Britain’s Tim Peake.
Michael David O’Gara
“Jupiter” Joe Martinez with his Mars Rover mini-car at AAA’s Spring Starfest at the
Woodlawn Cemetery in the Bronx on Mar 19.
Michael David O’Gara
Tele Vue Optics Founder Al Nagler demon-strates to AAA’s Sam Hahn a new product
for mating cell phones to eyepieces.
2
April’s Evening Planets: Jupiter will be in Leo the
Lion all night this month. Mercury is between Pisces the
Fish and Aries the Ram for an hour after sunset in the middle
of April. Mars will be in Scorpio the Scorpion. Saturn will
be between Scorpio and Ophiuchus the Serpent Bearer as of
midnight and rising earlier every night until 10 PM by the
end of the month.
April’s Evening Stars: The Winter Triangle will be up
in April until around 10 PM: Sirius, the brightest star viewed
from Earth is in Canis Major the Great Dog, Betelgeuse is in
Orion the Hunter, and Procyon is in Canis Minor the Small
Dog. Spot Capella in Auriga the Charioteer, Aldeberan in
Taurus the Bull, and bright Castor and Pollux in Gemini the
Twins. Also find the stars of constellations Cassiopeia, Her-
cules, Perseus, Draco, Virgo, Leo, Libra, and Ursa Major
and Ursa Minor (the Big and Little Dippers).
April’s Morning Planets: Venus will be in Pisces for
an hour before sunrise. Mars will be in Scorpio, and Saturn
will be between Scorpio and Ophiuchus until sunrise. Jupiter
can be seen in Leo until sunrise, setting earlier every night
until 4 AM by the end of April. Neptune is in Aquarius the
Water Bearer for about 2 hours before sunrise. Dwarf Pluto
is in Sagittarius the Archer from 3 AM until sunrise.
April’s Morning Stars: Spot the Summer Triangle of
Vega in Lyra the Harp, Deneb in Cygnus the Swan, and Al-
tair in Aquila the Eagle as of 2 AM and earlier every night.
Look for reddish Antares in Scorpius, Arcturus in Boötes the
Herdsman, and Spica in Virgo the Virgin, along with the
stars of constellations Leo, Hercules, Libra, Sagittarius, Cas-
siopeia, Draco, Ursa Major, and Ursa Minor.
Apr 6 Venus is 0.6° south of Moon dawn
Apr 7 New Moon at 7:25 AM
Moon at perigee (221,900 miles away)
Apr 13 First Quarter Moon at 11:59 PM
Apr 16 Mars stationary
Apr 18 Jupiter 2° north of Moon at midnight
Apr 22 Full Moon at 1:25 AM
Moon at apogee (252,500 miles away)
Apr 23 Lyrid meteor shower peaks dawn
Apr 24 Mars 5° south of Moon at midnight
Apr 28 Mercury stationary at midnight
Apr 29 Last Quarter Moon at 11:30 PM
Times given in EDT.
WHAT’S UP IN THE SKY
April 2016
Occultation of Aldebaran
This month, one of the brightest stars in the sky will dis-
appear from view, blotted out by the Moon. The lunar
occultation of Aldebaran has been observed for over 1,500
years, and its regularity can be predicted. The Apr 10 lunar
occultation of the bright, orange star is one of a current series
of 49 events that began in Jan 2015 and will continue until
Sep 2018. Occurring roughly every 18 years, the next series
won’t begin until 2033.
What is occultation? Occultation occurs
when one celestial
object passes in front
of another and ob-
scures it from view.
It happens more often
with faint stars, but
the bright first-
magnitude Aldebaran
will disappear behind
a crescent Moon in
the late afternoon of
Apr 10, winking out
of sight, and reappearing at nightfall as the Moon passes.
What is the history behind Aldebaran?
The regular lunar occultation of Aldebaran led to the discov-
ery of the proper motion of stars. By observing the occulta-
tion, Edmund Halley calculated in the 1700s that Aldebaran
must have changed its position in the sky over time. About
450,000 years ago, Aldebaran was actually the North Star. In
fact, it shared that honor with Capella, as those two stars
were very close together in the sky at the time. Despite our
perception that stars are fixed, they are moving through space
in orbit around the galactic center, just as the Solar System is
also in motion. Meanwhile, Earth’s pole star changes during
the 26,000-year precession of the planet’s rotation axis, so
positions are always changing over the long-term.
Where can I see the occultation? The occultation of Aldebaran is only visible in the Northern
hemisphere. It can be seen in the New York area and along
the Atlantic coast, and you can view the phenomenon with
the naked-eye under clear skies by looking west to the cres-
cent Moon. Then, look for the Pleiades and Aldebaran, the
“eye” in the constellation Taurus the Bull. The star will hide
behind the dark side of the Moon and reappear on the lit side.
What is the Ancient Greek myth behind Taurus? Europa was the beautiful daughter of the Phoenician king of
Tyre. Overwhelmed by love, the god Zeus transformed him-
self into a magnificent white bull and seduced her. With
Europa on his back, he swam to the island of Crete, where
she became a queen. The continent Europe is named for her.
Zeus recreated the bull’s shape in the stars of the constella-
tion Taurus. Sources: timeanddate.com; earthsky.org.
Follow veteran sky watcher Tony Faddoul each month, as he points our minds and our scopes toward the night sky.
AAA Observers’ Guide
By Tony Faddoul
April “Skylights”
3
April 2016
up his cell phone to
Al for a demonstra-
tion, and the set-up
took less than one
minute. So easy!
Another advance-
ment from the mind
of a true genius,
Al’s new device will
surely bring more
people into the
world of amateur
astronomy.
Al also very generously donated a 32mm Plössl eyepiece
from Tele Vue as one of the raffle prizes, which the fortunate
Sam Hahn won. Other prizes included a Meade 50mm tele-
scope, won by Richard Lawrence; a Celestron 50mm Back-
pack Scope, won by Ficlias Dupres; a Lunar 3D Model, do-
nated by Tony Hoffman and won by Jada Aroyo; and a jewel-
ry set, donated by Mary McQueen Alford and won by Hailey
Lopez.
At the observing site, many families, including inquisi-
tive children, peered through the telescopes and asked lots of
questions about how telescopes work and why our view of the
heavens changes from season to season.
AAA’s Peter
Tagatac and I offered a
telescope clinic to help
new owners become
more familiar with
their scopes. New
club member Kate
Stewart and her friend
Alison Bryan came by
with a Celestron As-
tromaster 144mm
equatorially mounted
scope. By the end of
the evening, they were observing the Moon like the rest of the
AAA crew! I hope to see Kate and Allison at a future observ-
ing event, showing off the tips they picked up.
Although the sky was less than cooperative, a good time
was had by all. And gathering at Woodlawn Cemetery, with
its impressive Romanesque and Greek-style mausoleums and
obelisks, and beauti-
fully landscaped gar-
dens, was a pleasure
in itself; the unique
site certainly made up
for the cloud cover.
A great big
THANKS goes to all
the AAA volunteers
and observers who
made this year’s
Spring Starfest so
special!
2016 Spring Starfest (cont’d from Page 1)
galactic astronomy in the 1920s and 1930s: Edwin Hubble
and Fritz Zwicky. “Hubble discovered the universe and
Zwicky discovered dark matter,” said Gott, who studied with
Zwicky as a postdoc student at Caltech. Hubble was the first
to see that the Andromeda Nebula lies outside our galaxy, and
that there was a universe of galaxies beyond the Milky Way.
Hubble’s Law of Expansion in 1929 also convinced Einstein
that the universe was expanding.
But if there was a vast network of ever-expanding galax-
ies, how was it all held together? “What is the shape of the
universe,” Gott and others wondered.
At first, astronomers
believed galaxies were
evenly distributed
throughout the universe.
But evidence showed that
galaxies cluster in some
places while voids filled
space elsewhere. Two
competing theories
emerged for how these
clusters and voids were
organized. During the
Cold War, American cosmologists favored a model where
galaxies dominated in isolated clumps. The Soviet school
proposed a honeycomb pattern of galaxies punctuated by giant
voids. These theories are often referred to with food meta-
phors: meatballs floating in a low-density soup or holes with-
in high-density Swiss cheese walls. In the early 1970s, physi-
cist Yakov Zeldovich, a father of the Soviet atomic bomb pro-
ject, further hypothesized that galaxies formed from the frag-
menting of vast, thin, high-density surfaces, referred to as
Zeldovich pancakes.
In 1986, Gott was among the first to propose a less edi-
ble and more three-dimensional structure for the universe: a
sponge. In this arrangement, both the galaxy clusters and the
voids are interconnected: “So I’ve got clusters of galaxies
connected by filaments of galaxies,” he explained, “And there
are empty voids in the centers which connect to other empty
voids through low-density tunnels. This is a sponge-like net-
work. And, it’s symmetric. The insides and outsides are iden-
tical.” This structure is also referred to as the “ cosmic web.”
The genesis of Gott’s theory was a high school science
project. Using a set of colorful 3-D polygons, Gott demon-
strated to the audience a new class of infinite regular polyhe-
drons that he created while a student, published in 1967 as
“Pseudopolyhedrons.” This type of geometric arrangement
can be seen in the structure of atoms in metallic crystals. Con-
templating them later, he developed the idea for a similar ar-
chitecture for the universe.
Gott’s high school project was selected as one of 40 win-
ners of the Westinghouse Science Talent Search (now the Intel
Science Talent Search). He later served for many years as
Chair of the Judges for the competition. Gott’s pseudopolyhe-
drons may have paid for half of his college tuition at Harvard,
but we all came out winners. One kid’s project paved the way
for a new understanding of the structure of the cosmos.
AMNH Frontiers Lecture (cont’d from page 1)
Michael David O’Gara
Local kids enjoyed observing the Moon at AAA’s Spring Starfest in the Bronx.
Michael David O’Gara
Surayah White coordinated AAA’s 2016 Spring Starfest, along with John Benfatti.
Michael David O’Gara
New AAA Member Kate Stewart (left) and Alison Bryan attended a Telescope Clinic.
NASA, ESA, E. Hallman
In Gott’s “cosmic web,” galaxy clusters and voids are both interconnected.
4
April 2016
Getting to Know Gravitational Waves
By Jason Kendall
On Mar 11, I had the pleasure of discussing the re-
cent discovery of gravitational waves by LIGO (Laser In-
terferometric Gravitational Wave Observatory) with my
fellow club members at an AAA Astro Answers session at
the American Museum of Natural History. AAA likes to
offer these special events periodically to help us take a closer
look at astronomy news items that are shaking up the field.
Although they were only just detected, gravitational
waves (“GWs”), or ripples in spacetime, are nothing new.
Einstein predicted them a hundred years ago. He postulated
they exist, because nothing can travel faster than the speed of
light. For Newton, gravity worked instantly. But when mass-
es move, collide, or break apart, they change. As they do, the
mass distribution changes, and so does the total mass sum.
Therefore, gravitational influence changes with time. Gravity
sends a message through spacetime. Einstein formalized this
idea with General Relativity in 1915.
Einstein himself went back and forth about whether or
not GWs existed before finally settling on an answer. This
was because he saw an apparent contradiction. For a GW in a
simple binary star system, looking at the orbit edge-on, the
two masses approach and recede, periodically changing the
distribution of mass. But the coordinates of the stars them-
selves don’t change, only their physical distance as spacetime
warps. This is like stretching a meter stick, where the mark-
ings remain the same, but the length of the stick changes.
However,
Einstein wasn’t
sure if gravita-
tional waves
could be meas-
ured. Is the en-
ergy carried by a
GW imparted on
what it passes
through? This is
important, be-
cause in order to detect GWs, they have to leave a trace of
some kind. Ultimately, the physics community was convinced
when Richard Feynman posed his thought experiment of
“strings on a bead.” For beads on a very long string that are
susceptible to a tiny amount of friction, a wave passing
through will move the beads. The friction causes the string to
heat, and so the heat must come from the energy of the pass-
ing GW. With that settled, the search was on for GWs.
Many methods were put forth to detect gravitational
waves. One concept was to create an enormous pure bar of
aluminum that would “ring” if a GW passed through. But the
best idea was to use an interferometer. Originally designed by
Michelson and Morley to demonstrate that there is no prefer-
ence for the speed of light in a given direction, optical inter-
ferometers split a beam of light into two arms and reflect them
back to a detector, combining their amplitudes. Sizing up the
scheme, the LIGO facilities in Louisiana and Washington
State, which were constructed over 25 years and for billions of
dollars, each have orthogonal arms 4 km long. A split laser
beam of light sent along each arm is calibrated to reflect back
toward a detector with the returning waves out of sync, cancel-
ling any signal. If a GW passes through, there will be a differ-
ential stretching of spacetime between the mirrors at the ends
of the arms, and the returning light waves will be nudged into
sync, producing a signal. That signal translates to a frequency
of sound. LIGO doesn’t
see GWs, it hears them.
GWs pass though
everything. They don’t
get absorbed or focused by
anything. They simply
spread out and get
“dimmer,” or more specif-
ically, “quieter,” with dis-
tance. They move out-
ward from a source differ-
ently than light does.
Light goes in all direc-
tions, so it spreads out in a sphere and gets fainter as the dis-
tance squared. Gravitational waves are “plane waves” and can
be thought of as travelling on the sides of a cylinder. The cyl-
inder is centered on the source. Keep the height of the cylinder
the same, but widen out the top and bottom. If you get far
enough away, then the plane wave spreads out over a “front”
that looks more and more like the circumference of a circle,
which increases like the radius of the circle. When they are
very far from their source, they are extremely weak, so weak
that they become “linear.” Therefore, they don’t back-react on
themselves or on the masses they pass through.
By adding SINE waves of sound together to create a
waveform, the same way an audio engineer can add together
pitches to mimic an oboe, you can add up waves of gravity to
imitate a known source of GWs. The waves, if heard, would
be in the human hearing range. On September 14, 2015, LIGO
received a signal that lasted a quarter-second and was well
above the regular noise of the detector. The waveform that
arrived was identical to a calculated waveform for two black
holes colliding and merging, where each was about 30 solar
masses. The waveform produced a “chirp,” which is a quick
increase in pitch and intensity at the end of the event. There
chirp was detected at both LIGO facilities. The signals arrived
about 7 milliseconds apart, which is the time it takes light to
travel between the two LIGO detectors. What’s amazing is
that we also know exactly how long ago the black hole merger
occurred, because the intensity of a GW gets “quieter” with
AAA ASTRO ANSWERS
LIGO
Schematic of a LIGO interferometer with a GW approaching.
National Science Foundation
LIGO detected gravitational waves caused by a merger of two black holes 1.3 billion years ago.
M. Pössel/Einstein Online
Gravitational waves alternately stretch and squeeze spacetime both vertically
and horizontally as they propagate.
5
distance. It happened 1.3 billion light-years away.
During my presentation, I passed over this material with
great rapidity. I also provided the derivation of how gravita-
tional waves propagate through space according to General
Relativity. The mathematics involved are not your average
high-school fare, but it is truly hard to understand relativistic
phenomena without that framework. That’s why there are so
many crackpot “theories” of gravity out there. Many well-
meaning amateur scientists think that relativity must be false,
because it is so hard to explain it exactly using simple vocabu-
lary. Just Google around, and you’ll see there’s no end to the
“woo-woo.” Often you’ll find made-up words strung together
by people without mathematical knowledge or any concept of
the logic of natural philosophy, much less a desire for their
ideas to actually work in the real world. But I digress.
The best part of an AAA AstroAnswers event is the
questions. The questions were excellent, sharing some won-
derful thoughts and ideas and showing the depth of involve-
ment and understanding by members of the club. Many came
up with comments about graphics, especially the com-
mon “warped spacetime” images that are ubiquitous on the
web. In these, an object hovers above a downward-bending
sheet that looks like a stretched fabric. One audience member
this made it seem that the objects don’t “obey” the sheet by
being stretched themselves. Such portrayals always assume
an imaginary extra dimension into which spacetime
curves. One of the trickiest ideas to reconcile is that there are
no extra dimensions of space in the mathematics of relativi-
ty. Curvature of spacetime is effectively “crumpled”
or “longer” at locations near mass. The length is provided by
the “length of time,” which refers to time’s contribution to
total spacetime distance.
Others were fascinated by the strong analogies of gravi-
tational waves to sound. However, the analogy breaks down
when thinking about the medium. The GW medium is the
distance of space and time itself, not air or ether or steel or
water. This motivates the common notion of the “fabric” of
spacetime. However, a fabric is a thing, not a space. So
again, the mathematics helps us understand spacetime by giv-
ing us the correct language to talk about it.
The language of the Aborigines of Australia uses a lim-
ited number system: none, one, two, three, many. They walk
huge distances across the outback by singing songs, and they
measure those distance by the length of the song sung to get
there. They do not have a concept for tiny increments of time,
like milliseconds or microseconds, nor do they distinguish
them from one another. Their measurements are never pre-
cise. But one’s language reflects one’s needs, and the Aborig-
ines do not need to know the exact amount of steel required to
build 10,000 cars. Likewise, our language does not exactly fit
spacetime, because it is not something we ever “use.” So, we
must teach ourselves a new language, powered by mathemat-
ics, that can clarify the relationships between space and time
and mass and energy. We must also unlearn certain ideas and
abandon some comfortable concepts to truly allow ourselves
to grasp the cosmos. The language and logic of lengths in non
-Euclidean geometries are not false, just unfamiliar and new,
and on Mar 11, AAA Members tried on some new words for
size.
April 2016
A Heroine Brings Dark Matter to Light
By Alan Rude
Dark Matter is all around, but
we can’t see it; we can only detect
its effects on a cosmic scale. It
makes up 23% of the universe. Visi-
ble ordinary (baryonic) matter – peo-
ple, stars, galaxies – is a mere 4%,
while “dark energy,” which we also
can’t see, represents 73% of the uni-
verse’s mass-energy. So how do we
know dark matter exists? How do
you measure what you cannot see?
The answer lies in the work of Vera Rubin, an astronomer
who studied at Cornell and Georgetown. Now 87, she has yet
to receive a much-deserved Nobel Prize. In the 1970s, Rubin
was working with colleague Kent Ford on orbital mechanics.
Ford had developed an extremely sensitive spectrometer that
they used make Doppler observations of the orbital speeds of
stars in spiral galaxies. They immediately discovered some-
thing unexpected. The stars in the sparsely populated outer
regions of a galaxy moved as fast as those closer to their galac-
tic center. This motion is totally different from what we see in
our Solar System: Earth, 93 million mi from the Sun, orbits
faster than Neptune, about 2.9 billion mi away.
This posed a problem, because the visible matter did not
have enough mass to hold such rapidly moving stars in their
orbits. The galaxies should fly apart. There had to be a tre-
mendous amount of unseen mass in the outer galactic regions
to generate the needed gravity, carrying the peripheral stars and
clouds along at speeds comparable to velocity of the inner ma-
terial and creating this “Rotation Effect.” Fritz Zwicky had
observed in 1933 that galaxies inside a cluster also move faster
than they should, due to what he then called “dark matter.” 40
years later, Rubin came along to prove him right. Rubin
studied hundreds of spiral galaxies, and her calculations
showed that ten times as much mass came from the dark matter
as could be accounted for by the visible matter. Nearly 90% of
galactic mass was invisible. “What you see in a spiral galaxy,”
Rubin concluded, “is not what you get.”
We know what dark matter does but not what it is. Many
believe it derives from a subatomic particle, with the leading
candidate being the WIMP (Weakly Interacting Massive Parti-
cle). A WIMP is a theoretical particle predicted by the Theory
of Supersymmetry, but it has yet to be observed. The Large
Hadron Collider at CERN hasn’t found it. Alternatively, some
propose it may be a quantum field superfluid that condensed in
puddles to “seed” galaxies and galaxy clusters. But such a
quantum field would be tied to spacetime, and would require
modifications to General Relativity.
Neither the particlists nor the superfluidists have evidence
to back up their positions. However, the current pace of scien-
tific progress suggests that may change soon. If only the
recognition of such important discoveries, like Vera Rubin’s,
could keep up. Sources: Cosmic Horizons:
Astronomy at the Cutting Edge; Back Reaction; space.com.
UNDERSTANDING THE UNIVERSE
Carnegie Institution of Washington
Vera Rubin in 1974 exam-ining photographic plates.
6
April 2016
Talking Next Gen Space Scopes at NYPL
By Pietro Sabatino
On Mar 16, the New
York Public Library
hosted a discussion of
Telescope, a new docu-
mentary about NASA’s
James Webb Space Tele-
scope (JWST). The film,
which aired on the Discov-
ery Channel in late Febru-
ary, was directed by Na-
thaniel Kahn. It features
behind-the-scenes footage
of construction of the
JWST, which is slated for
launch in 2018, as well as
interviews with the scien-
tists and engineers in-
volved. At the forefront of
the project, and featured throughout the film, is Matt Moun-
tain, the appointed telescope scientist for the JWST. Moderat-
ed by Paul Holdengräber, Kahn and Mountain spoke to the
NYPL audience about JWST’s mission, the history leading up
to its creation, and the importance of pushing the envelope in
humanity’s scientific exploration and understanding.
The first question Holdengräber asked Kahn and Moun-
tain was not about the film, but about books: “Of the books
found in the NYPL’s rare book collection, which spoke to you
the most?” Mountain replied that for him it was an original
1543 edition of Nicolaus Copernicus’s De revolutionibus orbi-
um cœlestium (On the Revolutions of the Heavenly Spheres).
The connection of that work to telescopes and our understand-
ing of the universe was as poignant as it was relevant.
Copernicus posited that the Earth revolves around the
Sun, in contrast with the prevailing belief in his time that the
Earth is fixed as the center of the universe with all other bod-
ies orbiting it. Yet Copernicus couldn’t directly observe the
motions that would prove his theory. It wasn’t until Galileo
built his own telescope in 1609, after hearing of the new
Dutch invention “for seeing things far away as if they were
nearby,” and observed Jupiter’s moons that some progress
was made. Here, for the first time, were observations that
directly contradicted the geocentric model, revealing that not
all heavenly bodies orbit the Earth. Kahn noted that even to-
day many people “are still struggling with the idea that we’re
not at the center of the universe.” This was a topic that the
panel would return to throughout the evening. How do we
respond to new knowledge that shows us just how small we
really are in the universe? Mountain had a very succinct an-
swer to this: “Just get over it.”
The JWST will serve as a successor to the Hubble Space
Telescope, which was launched over 25 years ago. Hubble
has allowed us to peer farther into space than ever before.
One of its images, known as Hubble Deep Field, aimed the
telescope at an empty patch of sky less than 3 arcminutes
wide. After taking long exposures, what they found in this not-
so-empty space were about 3,000 objects, all but 3 of which
were galaxies. Extrapolating that figure across the entire sky
provides an estimate of 100 billion (1011) galaxies in the uni-
verse. And if every galaxy contains 100 billion stars, some
quick multiplication yields 1022 stars out there. Each one of
those stars is likely to have at least one planet orbiting, which
gives us a lower bound for the total number of planets in the
universe. Thanks to Hubble, implications are mounting that we
may one day find other planets that can support life, or even
one that could sustain human life – “Earth 2.0.”
But there is a limit to what Hubble can observe. Hubble’s
instruments are mainly sensitive to visible light, and the pic-
tures it sends back represent a view that is fairly similar to
what we would be able to see with our own eyes. But due to
the red-shift of light traveling through our expanding universe,
extremely distant galaxies are entirely out of the visible range.
Their light resides in the infrared portion of the electromagnet-
ic spectrum, rendering them invisible to us and to Hubble.
Enter the James Webb Space Telescope. The JWST is
sensitive to both the near and mid-infrared wavelengths, and it
will allow us to see farther back in time to observe more distant
galaxies. Its sensitivity to infrared light will also help scientists
learn more about the formation of stars and planets within neb-
ulae, as the JWST will be able to peer through the dense gas
clouds and dust that block visible light. In addition, the
JWST’s 6.5-meter mirror, comprised of 18 small mirrors that
act together, is both larger and lighter than the one on Hubble.
In its operational form, the JWST is bigger than the
rocket that will launch it. Engineers have designed it to fold up
inside the rocket and then unfold on its way into orbit. The
JWST will orbit almost one million miles above the Earth at
what is known as the second Lagrange point (L2). This is a
gravitationally stable point between the Earth and the Sun.
Unlike Hubble, which orbits at a mere 350 miles above us
within the Earth’s magnetosphere, the JWST will be precluded
from any servicing or rescue missions; it’ll be too far away.
For 400 years, telescopes have transformed and shaped
our view of the universe and our place in it, and the James
Webb Space Telescope is the newest iteration of that tool. We
live in an exciting time of scientific exploration and innova-
tion, and the JWST will push the boundaries of what is possi-
ble, “which is the only way to advance our knowledge,” said
Mountain. While this knowledge leaves some feeling lost in
the immensity of the universe, to them I can only echo Moun-
tain: “Just get over it.” Sources: www.discovery.com; nypl.org; jwst.nasa.gov; wiki.
ASTRO TALKS
James Webb Space Telescope
A full-scale model of NASA’s James Webb Space Telescope.
AAA Announcement
The Annual Meeting of the Amateur Astronomers
Association will be held on Wednesday, May 18, 2016
at the Downtown Community Center,
located at 120 Warren Street in Manhattan.
All AAA members are encouraged to attend.
Refreshments will be served beginning at 6:30 p.m.
Meeting starts at 7:30 p.m.
We look forward to seeing you there!
7
Out of This World An Astronaut’s Final Mission Makes NASA History
In March, NASA’s Scott Kelly retired from the space agency, shortly after returning
from his 340-day mission to the International Space Station, the longest ever for an Ameri-
can astronaut. “I think the only big surprise was how long a year is,” said Kelly, who cele-
brated two birthdays during the mission. “It seemed like I lived there forever.” During Kelly’s
historic mission, which was shared with Russia’s Mikhail Kornienko, nearly 400 science experi-
ments were conducted, including many to support future long-duration missions, looking at
weightlessness, isolation, radiation, and psychological stress. “Scott’s contributions to NASA are
too many to name,” said Brian Kelly, director of Flight Operations at the Johnson Space Center.
“In his year aboard the space station, he took part in experiments that will have far-reaching ef-
fects, helping us pave the way to putting humans on Mars and benefiting life on Earth.” One major research area involved fluid
shifts in the body in zero gravity, which can affect vision and intracranial pressure, and must be conquered before a lengthy Mars
mission. Kelly also participated in unique comparative studies done in partnership with his Earthbound identical twin brother,
Mark, also a former NASA astronaut. This last mission was Kelly’s fourth, and with it he achieved the American record for cumu-
lative time in space with 520 days. “Records are meant to be broken,” Kelly said, “I am looking forward to when these records are
surpassed.” He won’t have to wait long. Last month, U.S. astronaut Jeff Williams launched to the ISS for a half-year mission that
will garner him 534 cumulative days in space. Williams, who last visited the ISS in 2010, was the first astronaut to live-Tweet
from space. Kelly embraced social media over his 144 million-mile journey above the Earth, posting over 700 astonishing photos
of the planet on Instagram and Tweeting 2,000 times, including a video where he dressed in a gorilla suit and chased Britain’s Tim
Peak to “Yakety Sax.” “Go big or go home,” Kelly said, “I think I’ll do both.” AMW Sources: nasa.gov; phys.org; nytimes.com.
Hubble Hubbub A Long Time Ago in a Galaxy Far, Far Away
In March, astronomers using the Hubble Space Tele-
scope measured the farthest galaxy we’ve ever seen in the
universe. 13.4 billion light-years away toward the constella-
tion Ursa Major, the very young GN-z11 shined brightly just
400 million years after the Big Bang. “We’ve taken a major
step back in time, beyond what we’d ever expected to be able
to do with Hubble,” said principal investigator Pascal Oesch,
who led the international team in the study. Many astrono-
mers thought that only the new James Webb Space Telescope,
scheduled to launch in 2018, would be able to see galaxies
this far away. With this find, scientists now suspect that many
of the bright galaxies previously imaged in the Hubble Deep
Field may be much further away than thought. The study
used Hubble’s Wide Field Camera 3 to measure the distance
to GN-z11 with spectroscopy, determining its redshift. Due to
expansion of the universe, the light of distant objects is
stretched to longer, redder wavelengths. “This is an extraordi-
nary accomplishment for Hubble. It managed to beat all the
previous distance records held for years by much larger
ground-based telescopes,” said investigator Pieter van Dok-
kum. Hubble and the infrared Spitzer Space Telescope imag-
es show GN-z11 is a
billion solar masses.
It’s 25 times smaller
than the Milky Way,
but growing 20 times
faster. Only a couple
hundred million years
after the very first stars
were born, this young
galaxy is forming them
astonishingly fast!
AMW Source: nasa.gov.
April 2016
Celestial Selection of the Month Reflection Nebula M78
1,600 light-years away
in the constellation Orion is a
nebula that’s got the blues.
Interstellar dust molecules in
M78 scatter shorter blue wave-
lengths of light from nearby
stars more than longer red
wavelengths, in the same way
that molecules in Earth’s at-
mosphere scatter light to make
our sky appear blue. Dust in
M78 also absorbs light, creat-
ing light-blocking dark streaks.
M78 is the brightest of a group of reflection nebulae found in
the Orion Molecular Cloud Complex, which is one of the
most active stellar formation regions in our night sky. It is
home to 45 low-mass, irregular variable stars of changing
brightness and spectral type. These main sequence stars are in
the very first stages of their stellar lives. 17 outflow sources
called Herbig-Haro objects have also been found in M78.
They form when jets of matter ejected from the young stars
collide with clouds of gas and dust at great speeds. The nebu-
la glows from the light of two recently formed bright, blue B-
type stars of 10th magnitude: “Two large stars, well defined,
within a nebulous glare of light resembling that in Orion’s
sword,” described William Herschel in 1783. He was less
confident about other aspects, saying, “I shall suspend my
judgement till I have seen it again in very fine weather, tho’
the night is far from bad.” M78 was first discovered in 1780
by Pierre Mechain and catalogued later that year by Charles
Messier. It can be spotted with binoculars or a small tele-
scope as a hazy patch a few degrees northeast of Orion’s Belt.
AMW Sources: universetoday.com; nasa.gov; messier-objects.com.
NASA, ESA, P. Oesch, G. Brammer, P. van Dokkum, G. Illingworth
At 13.4 billion light-years in the past, GN-z11 has bright, young, blue stars, but its light has been stretched to longer wave-lengths by the expansion of the universe.
European Southern Observatory
Shorter wavelength blue light is scattered more by molecules in M78, just as it is in Earth’s sky.
NASA/Bill Ingalls
NASA’s Scott Kelly returned to Earth on Mar 2 from his historic
340-day mission at the ISS.
8
A Message from the AAA President
Hello AAA Members:
Spring is finally here! With the warmer weather comes more
observing, and many locations resume this month. Be sure to check
the AAA website for observing session updates and other events at
www.aaa.org/calendar.
It was great seeing many of you at our annual Spring Starfest in
March at Woodlawn Cemetery in the Bronx. Despite the clouds, we
had a wonderful turnout. Many thanks go to all the volunteers and
observers who made the event possible. Thanks also to Jason Kendall
for the AAA AstroAnswers event last month, where he spoke to a great
crowd about the recent discovery of gravitational waves by LIGO.
Don’t miss the next talk in the AAA Lecture Series at AMNH on
Apr 1 with Niel Brandt from Pennsylvania State University presenting
"A Good Hard Look at Cosmic Supermassive Black Hole Growth". This
season's full lecture schedule is available at www.aaa.org/lectures.
And come say hello to your fellow AAA Members at this year’s
NEAF from Apr 9-10 at Rockland County Community College , where
we will have a booth staffed with volunteers representing the club.
Marcelo Cabrera
President, AAA
April 2016
Eyepiece Staff April 2016 Issue
Editor-in-Chief: Amy M. Wagner Copy Editor: Richard Brounstein
Contributing Writers: Bart Erbach, Jason Kendall, Tony Faddoul, Michael O’Gara, Alan Rude, Pietro Sabatino, and Amy Wagner
Eyepiece Logo and Graphic Design: Rori Baldari
Administrative Support: Joe Delfausse
Printing by McVicker & Higginbotham
APRIL 2016
FRI, Apr 1 Next: May 6
Lecture at the American Museum of Natural History, P
@ 6:15 pm – 8 pm
“A Good Hard Look at Cosmic Supermassive Black Hole Growth” pre-
sented by Penn State’s Niel Brandt. Free admission; open to the public.
(In the Kaufmann Theater; Enter at 77th St)
FRI & SAT, Apr 1, 2, 8, 9, 15, 16, 22, 23, 29, 30 Next May 6 & 7
Observing at Lincoln Center – Manhattan, PTC
@ 7:30 pm – 9:30 pm
SAT, Apr 2 Next May 7
Solar Observing at Grand Army Plaza – Brooklyn, PTC
@ 11 am – 1 pm
Observing at Brooklyn Museum Plaza – Brooklyn, PTC
@ 9 pm – 11 pm
SUN, Apr 3 Next May 1
Solar Observing at Central Park – Manhattan, PTC
@ 1 pm – 3 pm
TUE, Apr 5, 12, 19, 26 Next May 3
Observing on the Highline – Manhattan, PTC
@ 7:30 pm – 9:30 pm (Solar Observing begins @ 6 pm on Apr 12)
SAT, Apr 9 Next May 14
Observing at Great Kills – Staten Island, PTC
@ 8:30 pm – 11 pm
SAT & SUN, Apr 9 & 10
2016 North-East Astronomy Forum in Suffern, NY, PT
It’s Pluto Mania at this year’s NEAF! as Rockland Astronomy Club hosts
the world’s largest astronomy expo with vendors, workshops, solar ob-
serving, raffles, and more at SUNY Rockland Community College.
Speakers include New Horizons’ Alan Stern and Alice Bowman, Alden &
Annette Tombaugh, and Kevin Schindler of the Lowell Observatory.
(For tickets visit http://rocklandastronomy.com/neaf.html.)
FRI, Apr 13 Next May 13
Observing at Riverdale – Bronx, PTC
@ 8 pm – 10 pm
FRI, Apr 15
Observing at Carl Schurz Park – Manhattan, PTC Next May 20
Observing at Floyd Bennett Field – Brooklyn, PTC Next May 6
@ 8 pm – 11 pm
SAT, Apr 16
Observing at The Evergreens Cemetery – Brooklyn, PTC
@ 6:30 pm – 9:30 pm
SAT, Apr 29
Observing at Gantry Plaza State Park – Queens, PTC
@ 8 pm – 10 pm
M: Members only; P: Public event; T: Bring telescopes, binoculars; C: Cancelled if cloudy.
For location & cancellation information visit www.aaa.org.
AAA Events on the Horizon
The Amateur Astronomers’ Association of New York Info, Events, and Observing: [email protected] or 212-535-2922
Membership: [email protected] Eyepiece: [email protected]
Visit us online at www.aaa.org.
Other Astronomy Events in NYC
FRI, Apr 1
@ 7 pm Columbia Stargazing/Lecture Series at Pupin Hall – Manhattan, F
“New Horizons: Pluto Encounter” with Lauren Corlies. Observing follows,
weather permitting. (outreach.astro.columbia.edu)
THU, Apr 5
@ 7 pm AMNH 2016 Isaac Asimov Memorial Debate – Manhattan, F
“Is the Universe a Simulation?” Hayden Planetarium Director Neil deGrasse
Tyson moderates a panel of experts as they discuss a science fiction notion
that has become a serious line of theoretical and experimental investigation.
(This event is sold out, so log on to amnh.org/live to watch the livestream.)
MON, Apr 18
@ 7:30 pm AMNH Frontiers Lecture (Hayden Planetarium) – Manhattan, X
“Gravitational Waves: Messengers from a Warped Universe” with Nergis
Mavalvala at the American Museum of Natural History. Learn how we
search for ripples in space-time and decode the information they carry about
the first moments after the Big Bang. (amnh.org)
TUE, Apr 26
@ 7 pm AMNH Astronomy Live (Hayden Planetarium) – Manhattan, X
“The Force Fields Around Spaceship Earth” with Jana Grcevich and AAA’s
Irene Pease. Discover the invisible fields that protect our planet and make
life on Earth possible. (amnh.org)
FRI, Apr 29
@ 7 pm Columbia Stargazing/Lecture Series at Pupin Hall – Manhattan, F
“The Explosive Origins of Our Elements” with Sarah Pearson. Observing
follows, weather permitting. (outreach.astro.columbia.edu)
F: Free; X: Tickets required (contact vendor for information); T: Bring telescopes, binoculars.
9
April 2016
Talking Next Gen Space Scopes at NYPL
By Rafael Ferreira
“There’s no such thing as a free lunch” when it comes to
black holes, says particle physicist Georgi Dvali. Dvali spoke
to club members and the public on Mar 4 as part of the 2015-
2016 AAA Lecture Series, presenting “The Secret Quantum
Life of Black Holes.”
Most work on black holes reflects assumptions from
classical physics, not taking into account quantum mechanics.
Dvali, a professor at New York University, instead approaches
these objects using particle physics and quantum gravity.
According to classical physics, black holes are featureless,
which means they exist more as a metaphysical object. Noth-
ing, not even light, can escape a black hole. But in the quan-
tum world, a black hole has three definite features: mass, an-
gular momentum, and electrical charge – and if a black hole
has features, then it can send and receive information encoded
in those features. These messages can then be read by an out-
side observer.
Dvali explained that the key to a basic understanding of
black holes is quantum criticality. A quantum critical point
(QCP) occurs when the temperature for phase transition of a
material is suppressed to absolute zero. And at absolute zero,
all of momentum ceases to exist! This notion informs our
understanding of how information is transcribed within a
black hole. Dvali is working on how to manufacture such a
system in his laboratory.
In a quantum world, the Planck length
constant represents the quantum of action, a product of energy
and time or of momentum and distance. Any action greater
than the Planck constant can be measured using classical
physics, but on the Planck scale, the quantum effects of gravi-
ty strengthen.
When we consider a black hole, it’s Gigantic, but it is quan-
tized through quantum critically occurring within it.
Dvali begins by denoting the speed of light as 1 light-second,
To understand such a system, Dvali first denotes that the
speed of light is 1 as to measure it in light-seconds or years
when talking about a Planck length and Planck max. These
two measurements are the two shortest lengths in nature that
are crucial to the understanding of black holes. When we think
of an object, we usually don’t consider the gravitational radius
or Schwarschild radius, M, that that object incurs if it were to
be suddenly compressed within that sphere, but nothing can
escape it, thus creating a black hole. This can be any object
with mass. A human, all the way to a Supergiant star.
Within the quantum world, we have to take into account
Heisenberg’s uncertainty. The uncertainty consists of the more
accurate your reading is for the first variable, the bigger the
price you have to pay for the second variable. For example, if
we want to send a compact message, we have to pay in pro-
ducing more energy just to send that particular message. In the
terms of a black hole, energy gravitates, thus information grav-
itates. If we want to send this information we will have to pay
the gravitational price by increasing the gravity of that system.
So, we have a limit as to the information we can compact into a
message. The planck length becomes a limit because we cannot
send any message shorter than a planck length. This bound is
called the Bekenstein entropy of a black hole, which is a bound
for any given variable state of the particle. This means any
particle of information can be either up or down, switched off
or on, 1 or 0.
Dvali, uses the example of taking a box and feeding it
information. Eventually the density is converted into a black
hole, and it will keep increasing in size the more you feed. The
limit now for this black hole is its gravitational radius, but
since since we can keep increasing the size by inputting more
information into the black hole, the size and information of a
black hole is infinite!
We can characterize a black hole as a spherical surface
with pixels of information on it due to the Bekenstein equation.
Bekenstein’s equation takes the surface area of a black hole
and measures it in Planck area pixels. Now in physics, we love
taking the limits to test how nature reacts under certain condi-
tions. Dveli shows when the planck constant becomes zero, the
planck length becomes zero. Thus the information becomes
infinite, but classical physics says it has no information. Dveli,
says “No assumptions are being made, only well knowledgea-
ble facts about the facts of nature are being used.”
So how can this be? If we consider these two state varia-
ble states as cubics then they can have a possibility of two
states. In a classical manner we have to pay the energy price
for storing information, but within a black hole storing infor-
mation becomes exponentially cheap. This is due to a black
hole taking into account of 1/N possible states dealing with the
sum of the energies. Since black holes pay a minimal price in
energy, and hold an infinite amount of information, they take
an infinite amount of time to decode data from it. This is the
price they pay for black holes consisting of gravitons. Gravi-
tons within the black hole have an attraction towards one an-
other, but this point of attraction is at the critical point. If they
are under or over attraction, then the black hole cannot stay
together. This is the remarkable event that occurs within a
black hole which Dveli is trying to solve in how to produce a
quantum computer, but there will be no free lunch in figuring
out how.
AAA LECTURE SERIES
10
Out of This World An Astronaut’s Final Mission Makes NASA History
In November, NASA mathematician Katherine Johnson, who calculated the flight
trajectories for Alan Shepard, the first American in space; John Glenn, the first Ameri-
can to orbit Earth; and the Apollo 11 moonshot, was awarded a 2015 National Medal of
Freedom from President Obama. Receiving the nation’s highest civilian award, she was
recognized for her critical work in U.S. space history. “Johnson’s computations have influ-
enced every major space program from Mercury through the Space Shuttle,” said NASA Ad-
ministrator Charles Bolden. Johnson joined NASA’s predecessor, the National Advisory
Committee for Aeronautics (NACA), in 1953 as a “computer,” one of the women recruited
specifically for the exacting and tedious work of performing measurements and calculations.
African-American women found openings there beginning in World War II. The success of the “computers” prompted NACA to
keep women on board and expand their employment even after the war, while other industries kicked women out of the workplace
to make room for men. Johnson, who graduated summa cum laude at the age of 18 from West Virginia State College, worked in
the Langley Research Center’s Guidance and Navigation Department: “I said, ‘Let me do it. Y ou tell me when you want it and
where you want it to land, and I’ll do it backwards and tell you when to take off.’ That’s my forte.” Glenn even requested that
Johnson personally check the calculations for his Friendship 7 flight, even though NASA had begun using electronic computers.
This former “computer” successfully transitioned her skills in the computer age, working at NASA until 1986. “Katherine G.
Johnson is a pioneer in American space history,” said Bolden, “She’s one of the greatest minds ever to grace our agency or our
country, and because of the trail she blazed, young Americans like my granddaughters can pursue their own dreams without a
feeling of inferiority.” AMW Sources: nasa.gov; aip.org; whitehouse.gov.
Hubble Hubbub A Long Time Ago in a Galaxy Far, Far Away
ESA and NASA’s Solar and Heliospheric Observato-
ry (SOHO) has illuminated our Sun for 20 years, revolu-
tionizing heliophysics. “SOHO changed the popular view of
the sun from a picture of a static unchanging object in the sky
to the dynamic beast it is,” said ESA’s Bernhard Fleck.
Launched in Dec 1995, SOHO observes the Sun from above
Earth’s atmosphere. Prior to SOHO, flares were thought to be
the only solar event with Earth effects. It revealed the exist-
ence of coronal mass ejections (CMEs), speedy, giant clouds
of charged material with their own magnetic fields, that can
cause geomagnetic storms. Meanwhile, its extreme ultraviolet
images first saw solar tsunamis – waves that ripple across the
Sun’s surface in conjunction with a CME. Their discovery
allows scientists now to predict when a CME is directed to-
ward Earth. SOHO also helped solve a neutrino mystery.
The number of a certain solar neutrino type observed at Earth
didn’t match predictions. SOHO showed they really were
emitted, leading to the discovery that neutrinos can change
their type on their path from the Sun, and to the 2015 Nobel
Prize in Physics. SO-
HO also happens to be
the best comet hunter
around. Last year, it
found its 3,000th comet
– that’s over three
times the number of
comets ever spotted
from Earth in all of
human history. Aver-
aging 200 new comets
a year, SOHO can see
12.5 million miles
beyond the Sun.
April 2016
Celestial Selection of the Month Reflection Nebula M78
Just 577 light-years
away in the constellation
Cancer lies a cluster of a
thousand stars, enjoyed by
observers since antiquity.
Visible to the naked eye, the
open cluster M44, also known
as the Beehive Cluster or the
Praesepe (Latin for “manger”),
is one of the closest to Earth.
With a magnitude of 3.7, only
the Pleiades (M45) and An-
dromeda Galaxy (M31) are
brighter among the Messier objects. Described by ancient
astronomers Hipparchus and Ptolemy, M44 was first viewed
in a telescope by Galileo in 1609. Though its stars are bound
by mutual gravitational attraction, mass segregation has con-
centrated the brighter, more massive stars at the core, while
dimmer, less massive stars are distributed to the outer halo of
the cluster. Most of M44’s stars are red dwarfs, while about
30% are dwarfs like our Sun. In 2012, two exoplanets –
Pr0201b and Pr0211b – were discovered to be orbiting two
different Sun-like stars in M44. Found with the 1.5-meter
Tillinghast telescope at the Smithsonian Astrophysical Obser-
vatory's Whipple Observatory in AZ, the Hot Jupiter gas gi-
ants are massive and orbit very close to their parent stars.
“These are the first ‘b’s’ in the Beehive,” said discoverer Sam
Quinn. M44’s stars are only 600 million years old, so the
planets are among the youngest discovered. The cluster is
also rich in metals, which may act like “’planet fertilizer,’
leading to an abundant crop of gas giant planets,” said NASA
scientist Russel White. Their discovery revealed that
planets can thrive in dense, extreme environments like clus-
NASA TV
NASA’s Scott Kelly returned to Earth from his historic 340-day mission at the ISS on March 2 in Kazakhstan.
NASA, ESA, P. Oesch, G. Brammer, P. van Dokkum, G. Illingworth
At 13.4 billion light-years in the past, GN-z11 has bright, young, blue stars, but it appears red in this Hubble image as its light has been stretched to longer wave-lengths by the expansion of the universe.
European Southern Observatory
Shorter wavelength blue light is scattered more by molecules in M78, just as it is in Earth’s sky.
11
Behold the Moon
By Stan Honda
The Moon is a windfall for night sky photographers:
it’s relatively large and it’s easy to predict where it will be
in the sky. Even for amateurs with modest equipment,
this celestial object offers endless variations. For New York-
ers, it’s also readily visible in our light-polluted skies.
Still, it’s worthwhile to get a glimpse of Earth’s natural
satellite away from town. Last fall, I found myself at Ship-
pensburg University in south-central Pennsylvania, giving
talks about photojournalism, when the planets Jupiter, Venus
and Mars approached each other in the pre-dawn sky. Ship-
pensburg is a small town of about 5,500 surrounded by farm-
land, so I thought I would have a decent chance of capturing
the planets away from the glare of big city lights. I woke up
at 4 AM on Oct 27 to try to photograph the rising trio.
Unfortunately, a thin layer of clouds had moved in over-
night, all but obscuring the view of the planets to the east. I
could only just make out Venus, the brightest of the three,
which showed up only faintly in a few photos I took. Turning
to the west, I was then confronted with the magnificent sight
of the nearly full Moon surrounded by a giant halo. It was
low above the horizon and seemed to hover over the tree line.
A lunar halo forms when moonlight refracts through
hexagonal ice crystals in the clouds, creating a ring with a
radius of about 22 degrees. A variation in the refraction caus-
es the inner part of the circle to be reddish in color and the
outer part to be bluish.
You don’t need an extra-long telephoto lens to take an
interesting picture of the phenomenon. The widest angle lens
I had with me was a 14-24mm zoom. Setting it at 14mm, I
was able to take in a great expanse of the sky and the two-lane
road below it. Since it was the middle of the night, I was able
to venture into the road and stand directly in the middle, with-
out any fear of traffic. From that vantage point, the halo nes-
tled into a dip in the trees, making a nice composition.
My camera was attached to a small tripod, and unlike
with many night sky photos, I chose a relatively short expo-
sure at 4 seconds, with a lens opening of f5.6 and an ISO of
800. In processing the image, I increased the contrast a bit to
April 2016
emphasize the halo, but the final image was still very close to
what it looked like in person.
Earlier in October, I had tried to photograph a crescent
moon in a conjunction with the same trio of planets, again
during pre-dawn hours. From the reservoir in Central Park, I
looked toward the east side of Manhattan as the Moon and
Venus rose from behind the buildings. While waiting for the
other planets to appear, I shot the crescent moon very near the
top of a Fifth Avenue apartment building. I used a 70-200mm
zoom set at 200mm and cropped in close around the building
and the Moon, focusing attention on the pair. As a result, the
Moon became more prominent in the frame and look as if I
had used a longer focal length lens.
Using an exposure of ½ second and lens opening of f4 at
ISO 6400 on my Sony a7S camera, I captured some detail in
the building, but the lit crescent was washed out. However,
the unlit side of the Moon reflecting earthshine showed up
nicely, although no detail on this “dark side” can be seen.
Normally, you can count on a new or nearly new Moon
photo to show off the seas and craters of the lunar surface that
are undetectable when the Moon is brighter around full phase.
But shooting details on a less luminous Moon and on a sur-
rounding landscape or cityscape can be difficult – often you
get one or the other. Luckily, crescent phases are very pictur-
esque, so you don’t need to show much detail on the orb to
make it interesting. If you overexpose the Moon and permit
earth shine, you still get a nice skyline-crescent Moon combo.
Keeping the Moon very low on the horizon helps too,
because atmospheric haze can cut the light down quite a bit.
Another trick is to find an opportunity to shoot a moonrise or
moonset right around sunset or sunrise, which will level out
the exposure difference between the Moon and the fore-
ground. The Sun helps illuminate the terrestrial objects, so
you can concentrate on an accommodating lunar subject.
FOCUS ON THE UNIVERSE
Explore more night sky photography at
www.stanhonda.com.
Submit your photography questions to [email protected].
Stan Honda is a professional photographer. Formerly with Agence
France-Presse, Stan covered the Space Shuttle program. In his
“Focus on the Universe” column, he shares his night sky images and
explores his passions for astronomy and photography.
Stan Honda
Fifth Avenue Moon: Sony a7S camera with a Nikon 70-200mm f4 lens at 200mm, exposure of ½ sec., f4,
ISO6400 at 4:28 AM.
Stan Honda
Lunar Halo: Nikon D800 camera with 14-24mm f2.8 lens at 14mm, exposure of 4 sec., f5.6, ISO 800 at 4:12 AM.