Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.aaa.org/EyepieceFiles/aaa/2016_04_April_Eyepiece.pdf Äàòà èçìåíåíèÿ: Sat Apr 9 02:32:01 2016 Äàòà èíäåêñèðîâàíèÿ: Sun Apr 10 03:39:24 2016 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: meteor shower

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.

Journal of the Amateur Astronomers Association of New York
April 2016 V
olume 65 Number 4; ISSN 0146-7662

AAA Brings its Starfestivities to the Bronx
AAA SPRING STARFEST By Michael David O'Gara On Mar 19, about 150 New Yorkers tiptoed through the tombstones of the Woodlawn Cemetery in the Bronx with hopes of seeing the splendors of a springtime sky at AAA's Michael David O'Gara "Jupiter" Joe Martinez with his Mars Rover annual Spring mini-car at AAA's Spring Starfest at the Starfest. The Woodlawn Cemetery in the Bronx on Mar 19. 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 generously brought nearly 20 telescopes for the event. AAA's Joseph 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 astronomer 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 l a his Delos and Delite MichaeVDavid O'Gars Founder Al Nagler demonTele ue Optic eyepieces. AAA's strates to AAA's Sam Hahn a new product for mating cell phones to eyepieces. Sam Hahn offered
2016 Spring Starfest (cont'd on Page 3)

Untangling the Cosmic Web
AMNH FRONTIERS LECTURE 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 cosmologist, spoke on Mar 11 at the American Museum of Natural History's Hayden Planetarium as part of its Frontiers Lecture Series, describing his latest book, T he Cosm ic W eb: Mysterious Architecture of the Universe. A br illia nt stor yteller , Gott took his audience time-travelling across the many theories throughout history on the structure of the universe. "He is one of the m ost innov ativ e think ers that ex ists," 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. "T here's nothing that any body in our f ield does that he doesn't think about in some new or unusual way ," sa id Tyson. "T hat m eans that som etim es it leads now here, but som etim es 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 questions of all time: "How is the stuf f of the univ erse put together?" With tr a ces of his na tive Kentucky dr a wl a nd a disa r ming sense of humor, Gott began, "T his is a story about a generation 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)

THIS MONTH: A A A 's O b ser v ing Season Begins! Plus A A A L ect ur e on A p r 1 and NEA F A p r 9/10.


April 2016

WHAT'S UP IN THE SKY
AAA Observers' Guide
By Tony Faddoul

Occultation of Aldebaran
This month, one of the brightest stars in the sky will disappear from view, blotted out by the Moon. T h e lu n a r 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 obscures it from view. It happens more often with faint stars, but the bright firstmagnitude 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 discovery of the proper motion of stars. By observing the occultation, 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 crescent 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 himself 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 constellation 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.

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, Hercules, 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 Altair in Aquila the Eagle as of 2 AM and earlier every night. Look for reddish Antares in Scorpius, Arcturus in BoÆtes the Herdsman, and Spica in Virgo the Virgin, along with the stars of constellations Leo, Hercules, Libra, Sagittarius, Cassiopeia, Draco, Ursa Major, and Ursa Minor.

April "Skylights"
Apr 6 Apr 7 Apr Apr Apr Apr Ap Ap Ap Ap r r r r 13 16 18 22 2 2 2 2 3 4 8 9 Venus is 0.6° south of Moon dawn New Moon at 7:25 AM Moon at perigee (221,900 miles away) First Quarter Moon at 11:59 PM Mars stationary Jupiter 2° north of Moon at midnight Full Moon at 1:25 AM Moon at apogee (252,500 miles away) Lyrid meteor shower peaks dawn Mars 5° south of Moon at midnight Mercury stationary at midnight Last Quarter Moon at 11:30 PM
Times given in EDT.

2


April 2016 2016 Spring Starfest (cont'd from Page 1) AMNH Frontiers Lecture (cont'd from page 1)

up his cell phone to Al for a demonstration, and the set-up took less than one minute. So easy! Another advancement from the mind of a true genius, Al's new device will surely bring more people into the Michael David O'Gara Surayah White coordinated AAA's 2016 world of amateur Spring Starfest, along with John Benfatti. astronomy. Al also very generously donated a 32mm PlÆssl eyepiece from Tele Vue as one of the raffle prizes, which the fortunate Sam Hahn won. Other prizes included a Meade 50mm telescope, won by Richard Lawrence; a Celestron 50mm Backpack Scope, won by Ficlias Dupres; a Lunar 3D Model, donated by Tony Hoffman and won by Jada Aroyo; and a jewelry set, donated by Mary McQueen Alford and won by Hailey Lopez. At the observing site, many families, including inquisitive 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 Ascha l O'Ga a tromaster 144mm MieweADavidMemrber Kate Stewart (left) and N AA equatorially mounted Alison Bryan attended a Telescope Clinic. 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 observing 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 beautifully landscaped gardens, 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 Michael David O'Gara Local kids enjoyed observing the Moon at Spring Starfest so AAA's Spring Starfest in the Bronx. special! 3

galactic astronomy in the 1920s and 1930s: Edwin Hubble and Fritz Zwicky. "Hubble discov ered the univ erse and Zwicky discovered dark matter," sa id 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 galaxies, how was it all held together? "W hat is the shape of the universe," Gott a nd other s wonder ed. 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 NASA, ESA, E. Hallman clusters and voids were In Gott's "cosmic web," galaxy clusters and voids are both interconnected. 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 metaphors: meatballs floating in a low-density soup or holes within high-density Swiss cheese walls. In the early 1970s, physicist Yakov Zeldovich, a father of the Soviet atomic bomb project, further hypothesized that galaxies formed from the fragmenting of vast, thin, high-density surfaces, referred to as Zeldovich pancakes. In 1986, Gott was among the first to propose a less edible and more three-dimensional structure for the universe: a sponge. In this arrangement, both the galaxy clusters and the voids are interconnected: "S o I'v e got clusters of galax ies connected by filaments of galaxies," he expla ined, " And there are empty voids in the centers which connect to other empty voids through low-density tunnels. This is a sponge-like network. And, it's symmetric. The insides and outsides are identical." This str uctur e is a lso r efer r ed to a s the " cosmic web." The genesis of Gott's theory was a high school science project. Using a set of colorful 3-D polygons, Gott demonstrated to the audience a new class of infinite regular polyhedrons that he created while a student, published in 1967 as "Pseudopoly hedrons." This type of geometric arrangement can be seen in the structure of atoms in metallic crystals. Contemplating them later, he developed the idea for a similar architecture for the universe. Gott's high school project was selected as one of 40 winners 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 pseudopolyhedrons 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.


April 2016

Getting to Know Gravitational Waves
AAA ASTRO ANSWERS By Jason Kendall On Mar 11, I had the pleasure of discussing the recent discovery of gravitational waves by LIGO (Laser Interferometric Gravitational Wave Observatory) with my fellow club members at an AAA Astro Answers session at the American Museum of Natural History. AAA lik es t o 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 masses 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 themselves don't change, only their physical distance as spacetime warps. This is like stretching a meter stick, where the markings remain the same, but the length of the stick changes. However, Einstein wasn't sure if gravitational waves could be measured. Is the energy carried by a GW imparted on National Science Foundation what it passes LIGO detected gravitational waves caused by a through? This is merger of two black holes 1.3 billion years ago. important, because 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 passing 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 preference for the speed of light in a given direction, optical interferometers 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 4

LIGO

Schematic of a LIGO interferometer with a GW approaching.

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, cancelling any signal. If a GW passes through, there will be a differential 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 specifically, "quieter," with distance. They move outM. PÆssel/Einstein Online ward from a source differ- Gravitational waves alternately stretch ently than light does. and squeeze spacetime both vertically and horizontally as they propagate. Light goes in all directions, so it spreads out in a sphere and gets fainter as the distance squared. Gravitational waves are "plane waves" and can be thought of as travelling on the sides of a cylinder. The cylinder 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


April 2016

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 gravitational 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 wellmeaning amateur scientists think that relativity must be false, because it is so hard to explain it exactly using simple vocabulary. 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 wonderful thoughts and ideas and showing the depth of involvement and understanding by members of the club. Many came up with comments about graphics, especially the common "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 relativity. 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 gravitational 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 giving us the correct language to talk about it. The language of the Aborigines of Australia uses a limited 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 precise. But one's language reflects one's needs, and the Aborigines 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 mathematics, 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. 5

A Heroine Brings Dark Matter to Light
UNDERSTANDING THE UNIVERSE By Alan Rude Dark Matter is all around, but we can't see it; we can only detect its effects on a cosmic scale. I t makes up 23% of the universe. Visible ordinary (baryonic) matter ­ people, stars, galaxies ­ is a mere 4%, while "dark energy," which we also can't see, represents 73% of the universe's mass-energy. So how do we Carnegie Institution of W ashington Vera Rubin in 1974 exam- know dark matter exists? How do ining photographic plates. 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 something unexpected. The stars in the sparsely populated outer regions of a galaxy moved as fast as those closer to their galactic 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 tremendous 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 material 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. "W hat y ou see in a spiral galax y ," Rubin concluded, "is not w hat y ou 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 Particle). 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 scientific 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.


April 2016

Talking Next Gen Space Scopes at NYPL
ASTRO TALKS By Pietro Sabatino On Mar 16, the New York Public Library hosted a discussion of Telescope, a new documentary about NASA's James Webb Space Telescope (JWST). T h e film , which aired on the Discovery Channel in late February, was directed by Nathaniel Kahn. It features behind-the-scenes footage of construction of the JWST, which is slated for launch in 2018, as well as James Webb Space Telescope A full-scale model of NASA's James interviews with the scientists and engineers inWebb Space Telescope. volved. At the forefront of the project, and featured throughout the film, is Matt Mountain, the appointed telescope scientist for the JWST. Moderated 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 Mountain was not about the film, but about books: "Of the book s found in the NYPL's rare book collection, which spoke to you the most?" Mounta in r eplied tha t for him it wa s a n or igina l 1543 edition of Nicolaus Copernicus's De rev olutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres). The connection of that work to telescopes and our understanding 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 bodies 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 "f or seeing things f ar aw ay as if they w ere nearby," a nd obser ved J upiter 's moons tha t some pr ogr ess 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 today many people "are still struggling w ith the idea that w e're not at the center of the universe." This wa s a topic tha t 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 answer to this: "Just get ov er 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 6

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 (10 11) galaxies in the universe. 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 pictures 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 electromagnetic 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 nebulae, 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 innovation, and the JWST will push the boundaries of what is possible, "w hich is the only w ay to adv ance our k now ledge ," said Mountain. While this knowledge leaves some feeling lost in the immensity of the universe, to them I can only echo Mountain: "Just get ov er it."
Sources: www.discovery.com; nypl.org; jwst.nasa.gov; wiki.

AAA Announcement
The A nnual M eet ing 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!


April 2016

Hubble Hubbub
A Long Time Ago in a Galaxy Far, Far Away In March, astronomers using the Hubble Space Telescope measured the farthest galaxy we've ever seen in the universe. 13.4 b illion ligh t -years away toward the constellation Ursa Major, the very young GN -z11 shined brightly just 400 million years after the Big Bang. "W e'v e tak en a m ajor step back in time, beyond what we'd ever expected to be able to do with Hubble," sa id pr incipa l investiga tor P a sca l Oesch, who led the international team in the study. Many astronomers 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. "T his is an ex traordinary accomplishment for Hubble. It managed to beat all the previous distance records held for years by much larger ground-based telescopes," sa id investiga tor P ieter va n Dokkum. Hubble and the infrared Spitzer Space Telescope images 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 NASA, ESA, P. Oesch, G. Brammer, P. van Dokkum, G. Illingworth At 13.4 billion light-years in the past, GN- galaxy is forming them z11 has bright, young, blue stars, but its astonishingly fast! light has been stretched to longer wave- AMW Source: nasa.gov.
lengths by the expansion of the universe.

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 wavelengths of light from nearby stars more than longer red wavelengths, in the same way that molecules in Earth's atmosphere scatter light to make European Southern Observatory Shorter wavelength blue light is our sky appear blue. Dust in scattered more by molecules in M78 also absorbs light, creatM78, just as it is in Earth's sky. 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 nebula glows from the light of two recently formed bright, blue Btype stars of 10th magnitude: "T w o large stars, w ell def ined, within a nebulous glare of light resembling that in Orion's sword," descr ibed Willia m Her schel in 1783. He wa s less confident about other aspects, saying, "I shall suspend m y judgement till I have seen it again in very fine weather, tho' the night is far from bad." M78 wa s fir st discover ed in 1780 by Pierre Mechain and catalogued later that year by Charles Messier. It can be spotted with binoculars or a small telescope as a hazy patch a few degrees northeast of Orion's Belt. AMW Sources: universetoday.com; nasa.gov; messier-objects.com.

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 American astronaut. " I t h in k t h e on ly b ig su r p r ise w as h ow lon g a y ear is ," sa id K elly, wh o celebrated two birthdays during the mission. "It seem ed lik e I liv ed there f orev er." During Kelly's historic mission, which was shared with Russia's Mikhail Kornienko, nearly 400 science experiments were conducted, including many to support future long -duration missions, looking at NASA/Bill Ingalls weightlessness, isolation, radiation, and psychological stress. " S cott's contributions to N A S A are NASA's Scott Kelly returned to too many to name," sa id Br ia n Kelly, director of Flight Operations at the Johnson Space Center. Earth on Mar 2 from his historic 340-day mission at the ISS. "In his y ear aboard the space station, he took part in ex perim ents that w ill hav e f ar-reaching effects, helping us pave the way to putting humans on Mars and benefiting life on Earth ." One ma jor r esea r ch a r ea 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 cumulative time in space with 520 days. "R ecords are m eant to be brok en," Kelly said, "I am look ing f orw ard to w hen these records are surpassed." He won't ha ve to wa it long. La st month, U.S. a str ona ut J eff Willia ms la unched to the ISS for a ha lf-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 hom e," Kelly said, "I think I'll do both." AM W Sources: nasa.gov; phys.org; nytimes.com. 7


April 2016

AAA Events on the Horizon
APRIL 2016
FRI, Apr 1 Next: May 6 Lecture at the American Museum of Natural History, P
@ 6:15 pm ­ 8 pm

Other Astronomy Events in NYC
FRI, Apr 1 @ 7 pm Columbia Stargazing/Lecture Series at Pupin Hall ­ Manhattan, F "N ew Horiz ons: 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 Univ erse a S im ulation?" 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 "Grav itational W av es: M essengers f rom a W arped Univ erse" 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 "T he Force Fields A round S paceship 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 "T he Ex plosiv e Origins of Our Elem ents" with Sarah Pearson. Observing follows, weather permitting. (outreach.astro.columbia.edu)
F: F ree; X: Tickets required (contact vendor for informat ion); T: Bring telescopes, binoculars.

"A Good Hard L ook at Cosm ic S uperm assiv e B lack Hole Grow th" presented 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 observing, 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.)

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

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

Eyepiece Staff
M: Members only; P: Public event; T: Bring telescopes, binoculars; C: Cancelled if cloudy.

For location & cancellation information visit www.aaa.org.

April 2016 Issue
Editor-in-Chief: Amy M. Wagner
Copy Editor: Rich a r d Br ou n stein
Contributing Writers: B ar t E r b ach , J ason K en d all, T on y Fad d ou l, Michael O'Gara, Alan Rude, Pietro Sabatino, and Amy Wagner Eyepiece Logo and Graphic Design: R or i B ald ar i Administrative Support: J oe Delf au sse
Printing by McVicker & Higginbotha m

The Amateur Astronomers' Association of New York
Info, E vents, and Obser ving: president@aaa. org or 2 12 -535-2922 Membership: members@aaa. org Eyepiece: editor@aaa.org

Visit us online at www.aaa.org.
8


April 2016

Talking Next Gen Space Scopes at NYPL
AAA LECTURE SERIES By Rafael Ferreira "T here's no such thing as a f ree 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 "T he S ecret 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. Nothing, not even light, can escape a black hole. But in the quantum world, a black hole has three definite features: mass, angular 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 outside 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 and time or of momentum and than the Planck constant can physics, but on the Planck scale, ty strengthen. of action, a product of energy distance. Any action greater be measured using classical the quantum effects of gravi-

When we consider a black hole, it's Gigantic, but it is quantized 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 pro9

ducing more energy just to send that particular message. In the terms of a black hole, energy gravitates, thus information gravitates. 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 conditions. 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 knowledgeable facts about the facts of nature are being used." So how can this be? If we consider these two state variable 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 information 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. Gravitons within the black hole have an attraction towards one another, 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.


April 2016

Hubble Hubbub
A Long Time Ago in a Galaxy Far, Far Away ESA and NASA's Solar and Heliospheric Observatory (SOHO) has illuminated our Sun for 20 years, revolutionizing heliophysics. "S OHO changed the popular v iew of the sun from a picture of a static unchanging object in the sky to the dynamic beast it is," sa id ESA's Ber nha r d F leck. 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 existence 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 toward 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. SOHO 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. AverNASA, ESA, P. Oesch, G. Brammer, P. van Dokkum, G. Illingworth At 13.4 billion light-years in the past, GN- aging 200 new comets z11 has bright, young, blue stars, but it a year, SOHO can see appears red in this Hubble image as its 12.5 million miles light has been stretched to longer wavelengths by the expansion of the universe. beyond the Sun.

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. European Southern Observatory Shorter wavelength blue light is With a magnitude of 3.7, only scattered more by molecules in the Pleiades (M45) and AnM78, just as it is in Earth's sky. 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 concentrated 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 Observatory's Whipple Observatory in AZ, the Hot Jupiter gas giants are massive and orbit very close to their parent stars. "T hese are the f irst `b's' in the B eehiv e," 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 f ertiliz er,' leading to an abundant crop of gas giant planets ," sa id NASA scientist Russel White. Their discovery revealed that planets can thrive in dense, extreme environments like clus-

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 American 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 com putations hav e inf luenced every major space program from Mercury through the Space Shuttle ," sa id NASA AdNASA TV ministrator Charles Bolden. Johnson joined NASA's predecessor, the National Advisory NASA's Scott Kelly returned to Earth Committee for Aeronautics (NACA), in 1953 as a "computer," one of the women recruited from his historic 340-day mission at specifically for the exacting and tedious work of performing measurements and calculations. the ISS on March 2 in Kazakhstan. 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, `L et m e do it. Y ou tell m e w hen y ou w ant 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 r equested tha t 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. " K atherine G. Johnson is a pioneer in American space history," sa id 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. 10


April 2016

Behold the Moon
FOCUS ON THE UNIVERSE 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. E ven for a ma t eu r s wit h mod est eq u ip m en t , this celestial object offers endless variations. For New Yorkers, 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 Shippensburg University in south-central Pennsylvania, giving talks about photojournalism, when the planets Jupiter, Venus and Mars approached each other in the pre -dawn sky. Shippensburg is a small town of about 5,500 surrounded by farmland, 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 overnight, 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 causes 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, without any fear of traffic. From that vantage point, the halo nestled into a dip in the trees, making a nice composition.

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.

Stan Honda

Fifth Avenue Moon: Sony a7S camera with a Nikon 70200mm f4 lens at 200mm, exposure of ½ sec., f4, ISO6400 at 4:28 AM.

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 surrounding landscape or cityscape can be difficult ­ often you get one or the other. Luckily, crescent phases are very picturesque, 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 foreground. The Sun helps illuminate the terrestrial objects, so you can concentrate on an accommodating lunar subject.

Explore more night sky photography at
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.

www.stanhonda.com.
Submit your photography questions to

stanhonda@gmail.com.

My camera was attached to a small tripod, and with many night sky photos, I chose a relatively shor sure at 4 seconds, with a lens opening of f5.6 and an 800. In processing the image, I increased the contrast

unlike t expoISO of a bit to 11

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.