Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.aaa.org/EyepieceFiles/aaa/2015_03_March_Eyepiece.pdf Äàòà èçìåíåíèÿ: Tue Mar 3 02:22:28 2015 Äàòà èíäåêñèðîâàíèÿ: Sun Apr 10 03:41:15 2016 Êîäèðîâêà: Ïîèñêîâûå ñëîâà: molecular cloud

NASA

For 2015, International Year of Light, Chandra X-ray Observatory released new pics like this one of Whirlpool Galaxy M51.

Journal of the Amateur Astronomers Association of New York
March 2015
Volume 63 Number 3; ISSN 0146-7662

Seeing is Believing: Hidden Galaxies Revealed
AAA LECTURE SERIES By Stan Honda Like driving with a dirty windshield, Andrew Baker tries to peer at what's behind clouds of dust in our universe. Somet im es, t h e d u st h id es en t ir e ga la xies. T h e Rutgers University astrophysicist spoke about the phenomenon of hidden galaxies in the distant universe on Feb 6 at the American Museum of Natural History, the latest in AAA's free, monthly lecture series. Baker began by thanking the U.S. taxpayers in the audience "for willingly or unwillingly" supporting his research, which is funded by the National Science Foundation, on the Green Bank Telescope in West Virginia. The 100-meterwide dish is the world's largest, fully steerable telescope, part of the National Radio Astronomy Observatory (NRAO). Interstellar dust is made of carbon, silicon and other elements produced in the outer envelopes of dying red stars. The dust absorbs visible light from stars and reradiates the light in the far infrared spectrum, or long wavelength radiation. When astronomers look at a portion of the sky, the missing optical light is a signpost for dust. "W e k now w hat's there ­ dust ­ because we know what's missing ­ light from stars," sa id Ba ker . He offered up slides of some well-known examples: the iconic shape of the Horsehead Nebula (Barnard 33) is the result of huge dust clouds in front of ionized gas; the Trifid Nebula (M20) is bisected by large regions of dust; and the Whirlpool (M51) and Black Eye (M64) Galaxies have extremely NAO The Horsehead Nebula's shape large dust lanes in their spiral is formed by interstellar dust structures. clouds in front of ionized gas. "Can dust hide an entire galaxy?" Ba ker a sked. He then quickly r eplied to his own question, "Y es! If all the light is m issing, w e m ight not ev en realize there is a galaxy at all." So how do you find these hidden galaxies? "W hen CO is Our Friend," a nswer ed Ba ker 's next slide. Most a ssocia tions with that molecule are negative, and although carbon monoxide (CO) is dangerous to humans on Earth, radio asAAA Lecture (cont'd on Page 4)

Diving in: Exploring Europa's Subsurface Ocean
WHAT IF??? Richard Brounstein NASA and ESA are planning a trip to Europe, er Europa, that is ­ not the Earth continent, but the icy moon of Jupiter that hides a salty, liquid water ocean beneath its surface. This feature makes the outer Solar System body a very special place, one of the very promising locaNASA tions where non-Earth life A liquid water ocean under the icy surface of Jupiter's moon Europa forms may actually exist. may be 60 miles deep. The American and European (perfect!) space agencies have announced a joint mission called JUICE (JUpiter ICy moons Explorer), which will launch in 2022 and arrive in orbit around Jupiter in 2030. During flybys of several Jovian moons, the probe will perform detailed reconnaissance of Europa to gain more information about it. The mission will collect high resolution images and study its surface features and processes. Europa's icy crust has been subject to continuous resurfacing by tectonic and thermal processes over tens of millions of years. Patterns of ice cracks, ridges, and displacement show signs of surface stress, and tidal flexing due to Jupiter's gravity keeps Europa's water warm enough to be liquid. Material is exchanged between the subsurface ocean and the ice crust in continuous processes. Studying Europa's surface is an important first step to exploring its ocean and the life forms that may reside beneath. Now, we have to figure out the best way to break the ice. Twenty years ago, the NASA spacecraft Galileo made a flyby of Europa and sent back to Earth the first data to suggest a 60-mile deep subsurface ocean. Since then, it has been a dream of astronomers and astrobiologists to explore it. We know here on Earth that where there is liquid water, there is life. So, it is only logical to suspect that Europa's salty ocean harbors life too. But even if we manage to make our way there on the nearly 400 million-mile trip, going for a dip will be a huge challenge. We don't know exactly the depth of Europa's ice layer ­ it could be tens of kilometers thick. So, we can't just drill a hole and go fishing. But, there may be a
Ocean Exploration on Europa (cont'd on Page 4)

THIS MONTH: A A A L ect ur e on M ar 6 and NA SA Sun/Ear t h Day at A M NH on M ar 21!


March 2015

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

Pluto and the Dwarf Planets
In 2006, the International Astronomical Union (IAU) changed Pluto's classification to a dwarf planet , defined as: "a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity...so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite." Dwarf planets are tiny, dim, and often in far-flung orbits, making them tough to find. Scientists estimate that dozens remain undiscovered. Here are the five most recognized. Pluto was discovered by Clyde Tombaugh in 1930 and named for the Roman god of the underworld (Hades, in Ancient Greece). The 1,455 milewide body has an extremel y elliptical orbit in a different plane than the eight planets of our Solar System. It orbits the Sun at an average distance of 39.3 au, taking 248 Earth years to complete a lap. Its five moons are named for elements of underworld mythology: Charon, Nix, Hydra, Kerberos, and Styx. The largest, Charon, is nearly equal in size to Pluto, forming a double system. NASA's New Horizons spacecraft is scheduled to reach Pluto in July 2015. It was still the ninth planet when the mission launched in early 2006. Ceres is the smallest of the dwarf planets at 590 miles wide, but the largest object in the Asteroid Belt between Mars and Jupiter. Discovered in 1801, it was named for the Roman grain goddess (Demeter, to the Greeks). It is nearest at only 2.8 au from the Sun and completes one orbit in 4.6 Earth years. It is thought to be an icy protoplanet, the only one not found in the Kuiper Belt. NASA's Dawn mission will arrive at Ceres this month for our first study of a dwarf planet. Haumea, discovered in 2003, has an elongated shape with a rocky interior, covered by a thin, icy crust. It is named for the Hawaiian goddess of fertility, and its moons are named for her daughters Hi`iaka and Namaka. Haumea is about as wide as Pluto at 1,200 miles, but it is 1/3 as massive. Haumea averages 43.2 au in its 283 Earth-year orbit. It completes one full rotation in less than four hours, making it one of the fastest-spinning bodies in the Solar System. Makemake, a p lu t oid (or b it in g b eyon d Nep t u n e), was discovered ten years ago and is named after the fertility god of the native people of Easter Island. Its surface is thought to be composed of frozen methane, ethane, and nitrogen. It is about 3/4 as big as Pluto and at 45.7 au from the Sun, it completes one orbit every 310 Earth years. Eris, a n ot h er p lu t oid , wa s fou n d in J a n u a r y 2005 a n d briefly considered our tenth planet. It was demoted by the IAU with Pluto. It is named for the Greek goddess of chaos and has one known moon named for her daughter, Dysnomia, the goddess of lawlessness. Eris is similar in size to Pluto but about 25% more massive. It has a highly elliptical orbit at an average distance of 67.8 au, which takes 557 Earth years to complete.
Sources: IAU; Encyclopedia Britannica; nasa.gov; space.com.

March's Evening Planets: Mars will be visible for
about an hour after sunset in Pisces the Fish. Venus will be visible for about 3 hours after sunset moving from toward Taurus the Bull. Uranus will also be in Pisces for about one hour after sunset in the first half of the month. Bright Jupiter is found in Cancer the Crab all night.

March's Evening Stars: The Winter Triangle will be
up in March until 11:00 PM with Sirius, the brightest star viewed from Earth, in Canis Major the Great Dog; Betelgeuse in Orion the Hunter; and Procyon in Canis Minor the Small Dog. Spot Capella in Auriga the Charioteer, Aldeberan in Taurus the Bull, Arcturus in Bootes the Herdsman, and bright Castor and Pollux in Gemini the Twins. Also find the stars of constellations Cassiopeia, Perseus, Cepheus, Draco, Virgo, Leo, Cancer, Corona Borealis, and the two Dippers during the month.

March's Morning Planets: Jupiter will linger in Cancer the Crab until dawn. Saturn be up in Scorpius the Scorpion after midnight and will stay until sunrise. Mercury is between Capricornus the Seagoat and Aquarius the Water Bearer during the first half of March for about an hour before sunrise. Later in the month, Neptune will be in Aquarius shortly before sunrise. Dwarf planet Pluto will be in Sagittarius the Archer a couple of hours before sunrise.

March's Morning Stars: Spot the Summer Triangle
around 3:00 AM, rising earlier every night, formed by Vega in Lyra the Harp, Deneb in Cygnus the Swan, and Altair in Aquila the Eagle. Look for reddish Antares in Scorpius the Scorpion, Arcturus in Bootes the Herdsman, and Spica in Virgo the Virgin, along with the stars of constellations Leo, Lyra, Hercules, Libra, Corona Borealis, Cassiopeia, Cepheus, Draco, and the two Dippers.

March "Skylights"
Mar 3 Mar 5 Ma Ma Ma Ma r r r r 8 13 19 20 Jupiter is 5° north of the Moon (morning) Full Moon at 1:05 PM ES T (smallest of 2015) Moon at apogee (252,515 miles from Earth) Daylight Saving Time begins Last Quarter Moon at 1:45 PM Moon at perigee (222,190 miles from Earth) New Moon at 5:35 AM Vernal Equinox at 6:45 PM Total Solar Eclipse (not visible in the US) Mars is 1° north of the Moon (at sunset) Saturn is 2° south of the Moon (morning) Moon pairs with Venus after sunset First Quarter Moon at 3:45 AM
Times given in EDT, unless noted.

Mar 21 Mar 22 Mar 27 2

Follow veteran sky watcher Tony Faddoul each month, as he points our minds and our scopes toward the night sky.


March 2015

Seen in Space
Citizen Scoobies Investigate a Spitzer Mystery and Thar She Blows! NuSTAR & XMM-Newton See Black Hole Wind

AAA Around Town
Workshop at Adorama On Feb 15, Michael Richmond of the Rochester Institute of Technology conducted a workshop for AAA at Adorama in Manhattan. H e teaches astronomy and physics and runs the RIT Observatory. He discussed urban observing Stan Honda and described how the human eye is a great instrument for observing variable stars, even in light -polluted skies. SH

Zooniverse.org is a citizen science website where anyone can help scientists classify data. Volunteers on T he M ilk y W ay Project found wha t they NASA/JPL-Caltech dubbed "yellowballs" in im- Citizen scientists discovered mysages taken by the Spitzer terious "yellowballs" in Spitzer data. Space Telescope. They had stumbled upon "a new w ay to detect the early stages of massive star formation," sa id Charles Kerton, co-author of a new study. "T he sim ple question of `Hmm, what's that?' led us to this discovery ." They'r e not really yellow ­ its just the color their infrared wavelengths are assigned, where green and red overlap. They occur mainly along the rim of green bubbles of organic molecules that are blasted out by a massive newborn star. Inside the bubbles is dust, red when warmed by the star. Analysis reveals that this new class of object formed before the green bubbles ­ representing an earlier phase of star birth. Their presence suggests the massive new stars are causing more starbirths, a phenomenon called triggered star formation. NASA and ESA are teaming up to figure out just how powerful supermassive black holes really are. T h eir space telescopes NuSTAR and NASA/JPL-Caltech XMM-Newton view co mpleWinds from supermassive black mentary high and low energy holes blast out in all directions. parts of the X-ray spectrum. Together, they observed "nearby" PDS 456, a luminous quasar powered by a black hole formed 10 billion years ago, and found that its 223 million mph radiation is blowing out not as a beam, but in all directions. "For an astronomer...PDS 456 is like a paleontologist being given a living dinosaur to study ," said Daniel Stern of NASA. As the black hole feeds, ionized particles are forced out of its accretion disk, inhibiting star formation and regulating its galaxy's growth. Having measured the wind's speed, shape, and size, scientists can now determine the black hole's strength. AMW Source: nasa.gov

Down to Earth
Forward Progress with a Backward Glance NASA's Earth Sciences Division has had a busy year, launching five m ission s, t wo in t h e p a st mon t h a lon e ­ Soil Moisture Active Passive (SMAP) and Deep Space Climate Observatory (DSCOVR). SMAP will make highresolution global maps of the Earth's soil moisture to track water availability and identify trends around the planet. It will help improve weather forecasts, monitor droughts, predict floods, gauge climate cycles, and hopefully, guide policy decisions. A major impact of climate change will be its societal effects on water supply, especially for food production. Meanwhile, renamed DSCOVR, the Earth observatory first proposed by Vice President Al Gore in 1998 called Triana finally launched last month, after sitting in storage during the Bush administration. The satellite was originally intended to gather data about global warming and also raise Earth awareness by taking a live image of the planet to be made available to the public on the internet. Redefined for funding purposes by President Obama, DSCOVR will primarily monitor solar wind in real-time and measure radiation, but it will still image the sun-lit side of the Earth, NASA monitoring ozone, aerosols, cloud The Deep Space Climate dynamics, land, and vegetation. Observatory (DSCOVR) AMW Sources: nasa.gov; nytimes.com. launched on Feb 11.

Telescope of the Month
The Aristarchos Telescope in Greece Named for the 3rd century BCE Greek astronomer who first proposed that the Earth revolved around the Sun, the Aristarchos Telescope is loca t ed a t t h e H elmos O b ser va t or y in t h e Northern Peloponnese, about 80 miles west of Athens, in one of the darkest areas in Europe. Operated by the National Observatory of Athens (NOA), it was inaugurated in 2007. The Aristarchos is currentNOA ly focused on the star system in planetary nebula KjPn8. In the constellation Cassiopeia, KjPn8 is unusually shaped with giant lobes. NOA scientists are trying to determine the distance to KjPn8 and the ages and energy output of its lobes. They disco vered that KjPn8 is about 6,000 light-years away and that its star system ejected matter into space three times: 3,200, 7,200, and 50 ,000 years ago. Its inner lobe is expanding at 208 miles/s, which suggests it is the result of an Intermediate Luminosity Optical Transient (ILOT) event. ILOTs happen when a massive star transfers material to a less massive companion, producing high -speed jets. So, the core of KjPN8 must be a binary system. The Aristarchos is a Ritchey-ChrÈtien Telescope with a hyperbolic 2.3m primary mirror and a hyperbolic secondary mirror. This design makes its large 1° field of view free of optical aberrations. But, wh ile RCTs are compact, like other Cassegrain reflectors (concave primary and convex secondary mirrors ), their hyperbolic mirrors are very expensive to fabricate, making telescopes like the Aristarchos rare. AM W Sources: helmos.astro.noa.gr.; universetoday.com. 3


March 2015

AAA Lecture (cont'd from Page 1)

tronomers love the stuff. The presence of CO corresponds with star-forming regions in galaxies: the molecular cloud in the constellation Taurus, which is filled with carbon monoxide, gave rise to the Pleiades. Very distant dusty galaxies have CO in their spectrum signatures. The instrument that is used in the search for CO is the Zpectrometer, a spectrometer that covers an ultra -wideband for a broad range of z, or redshift. Redshift tells us how far away a galaxy is. Our universe is expanding at an accelerating rate, and the furthest galaxies are receding the fastest. By the time their light reaches us, the radiation has increased in wavelength, shifting to the red end of the spectrum. More distant galaxies have more redshift. Baker uses the Zpectrometer to look for CO emission lines in the spectra of high redshift galaxies, with z between 1.9 and 3.4. The Zpectrometer is attached to the Robert C. Byrd Green Bank Telescope, which is located within the National Radio Quiet Zone, an area of about 13,000 square miles near the borders of Virginia and West Virginia. Cell phone towers and other radio services are restricted in the Zone, which was established by the FCC in 1958 to minimize harmful interference to the NRAO. Much to their chagrin, the Rutgers students who accompany Baker on research trips to the site are stranded without cell service for days. Unusually, the Zpectrometer's electronics are analog, which makes it lighter. It produces less heat than solid-state electronics. Describing recent findings, Baker presented data and images of a galaxy almost completely hidden by dust in visiOcean Exploration on Europa (cont'd from Page 1)

ble light, which was detected only by CO emission. Baker also uses the Zpectrometer to measure redshifts for galaxies that appear distorted because of gravitational lensing by a foreground object. He reconstructs what the galaxy looks like unlensed, especially its discrete starforming regions, which are Mark Swinbank (Durham) and Steve Longmore (SAO) brighter and more active in Distant dusty galaxy SMM J2135-0102 the distant galaxies of the is gravitationally lensed by a foreground galaxy cluster. Redshift measurements young universe. by the Zpectrometer on the Green Bank Baker also discussed Telescope reconstruct how it looks a new project with the Ata- without lensing (upper left), especially its four active star-forming regions. cama Large Millimeter Array (ALMA), located on the dry, 5,000-meter-high Chajnantor plateau in northern Chile, which will provide insight into star birth in the early universe. It is the largest and most sensitive instrument in the world at longer millimeter and submillimeter wavelengths. During the Q&A following the presentation, an audience member asked what Baker might report if he returned for another AAA lecture in ten years' time. He said that he'd hope to provide a better understanding of early galaxies. Optical and radio astronomers look at very different things, he explained, and once all the pieces of the puzzle are assembled, we might have a better idea of how galaxies evolved. most of Europa's oceanic life might be at the bottom instead, where tidal forces on the rocky interior could create volcanism or hydrothermal vents. We may not find complex life, like giant octopuses, but we might find microbes down there. So, don't hold out for a taste of Europ-ean shrimp cocktail just yet. But, there are no guarantees for microbes either; we know tidal flexing affects Europa's surface, but we can't be sure the inner rock seafloor is also tectonically active. While any discovery of extraterrestrial life would be significant, finding it so far away would suggest it evolved independently from life on Earth. If we find Martian life, it is likely have arisen from material exchanging back and forth with nearby Earth. It is doubtful that water from Europa could travel this far into the inner Solar System, escaping Jupiter's gravitational pull. Even more unlikely is the possibility that material from Earth could make its way to Europa unscathed. We can say with confidence that the only Earth material to reach Europa will be man-made probes. Studying independently evolved Europ-ean life forms could be a way to learn more about life outside our Solar System. How do they accomplish growth, reproduction, locomotion, metabolism, etc? If we find they are based on DNA, then there is a greater likelihood the molecule is fundamental to life everywhere in the universe. Life unlike us may be very like us indeed! Sources: researchgate.net; nasa.gov; space.com.
Richard Brounstein's "What If?" column tests the limits of our imagination

way in. In December 2012, the Hubble Space Telescope observed plumes of water vapor erupting from the south polar region of Europa. So, there is at least one spot where the ice is thin enough for water to escape, so maybe we can break in. A probe might Artist's concept for an underwater probe to explore Europa's subsurface ocean. gain access here, with minimal drilling. But, once we dive into Europa's ocean, where will we find life? If it is anything like Earth, then millions of living bacteria would be present in every 1.5 gallons of the water. A probe might meet with success right off the bat and find microbes on its first plunge. But, it is estimated that Europa's ocean has more than twice as much water as Earth. Finding life may be more difficult in such a vast body of water. Meanwhile, it is hardly adequate to use Earth oceans as a guide, when we have explored so little of them ­ less than 5% ­ how much do we really know about marine life? We do know that living organisms need more than just water. They need energy and nutrients, which are found in warmer waters. On Earth, most marine life lives in surface waters closest to sunlight. Topped by layers of thick ice, 4

­ can the improbable or impossible be reality one day?


March 2015

Still Lovin' Lovejoy
FOCUS ON THE UNIVERSE By Stan Honda I caught the comet bug after photographing Lovejoy in early January at the United Astronomy Clubs of New Jersey (a frosty adventure featured in the February Ey epiece), so I set out to capture it again. After consulting star charts, I discovered Lovejoy (C2014/Q2) would make a close approach to the Pleiades star cluster in mid -January, which could make for a nice composition. All I needed were some dark skies. I called my friend Rush Dudley in Albuquerque to verify the dependable New Mexico weather for the next week ­ reliably clear skies were forecast ­ and he suggested heading north to his brother-in-law Ron's house in Taos for best viewing. Using my trusty airline miles, I flew out to meet up with Rush on Jan 14. We drove up to Taos that afternoon. When we stepped out into Ron's backyard after dark, we were greeted by a lovely view of the Milky Way high overhead and the brilliant stars of Orion in the south. With a 50mm lens on a Nikon D800, mounted on an iOptron SkyTracker, I aimed above the Hunter to shoot the Pleiades and Aldebaran, an orange-ish star in Taurus. On the camera's screen, Lovejoy glowed green with a distinct tail and formed a triangle with the other two objects. Pretty good results for our first night out, I thought. Faint comets are usually best photographed with telescopes or long telephoto lenses. In Lovejoy's case, I think the best photos were taken with relatively moderate Stan Honda Comet Lovejoy and the Pleiades on Jan 15. lenses, 50mm to Nikon D800, 70-200mm zoom lens at 102mm on 135mm, on a fulliOptron SkyTracker mount, 90 sec., f4, ISO 3200. frame digital SLR (35mm to 90mm on cameras with APS -C-sized sensors). A telescope gave excellent close-in views of the comet, but a wider camera lens allowed me to include other objects, providing perspective. Having a familiar object in a night sky photo also adds a common reference point. Lovejoy speeding past the bright Seven Sisters made for a memorable image. I hadn't originally planned to use the 50mm lens ­ the choice was serendipitous. I realized the next morning, looking at the star charts again, that I could create a composite image of Lovejoy's progression past the Pleiades shooting over the next five nights with the same lens. For those five nights, we drove out of Taos to seek even darker skies, away from the city's light glow. Winding our way through the surrounding mountains, we found some spots well above the 7,000-foot elevation of the city, where we would experience new levels of cold. Many, many, many layers of clothing, hand and toe warmers, and frequent breaks in Rush's heated van kept us from freezing. 5

Each night, I shot with the 50mm lens, keeping the composite in mind, and then switched to a 70200mm zoom, set at about 100135mm, for a closer image. Lovejoy's tail Stan Honda was quite long A composite follows Lovejoy's progress over six nights from Jan 14-19, with the Pleiades (top and extended at center) and orange Aldebaran (left). Nikon D800 least to the edge with a 50mm lens on iOptron SkyTracker mount, each exposure 90 sec., f4, ISO 3200. of the frame. My best shot was taken this way, with a 90-second exposure at f4, at an ISO of 3200. The SkyTracker mount proved to be invaluable. It supported the camera/lens combination and tracked with fairly good precision for the long exposures. I also took a 300mm f4 lens with me, having gotten good results with it a week earlier in New Jersey. The lens is heavier than the 70-200, but the SkyTracker handled the bigger load. Jan 15 was an ultra -clear night, and I captured some great close-ups of Lovejoy with the longer telephoto lens, using the same exposure as I did with the zoom. Lovejoy moved rapidly in the sky past the Pleiades, at least 1° each night. This was my first experience photographing a comet over time from a dark site, and it was a productive trip. S k y & T elescope magazine featured my shot of the comet and Pleiades on the online gallery's "Editor's Pick" page (http://www.skyandtelescope.com/online-gallery/ lovejoy-passes-the-pleiades). And, A stronom y Picture of the Day posted some of my ima ges on " Sta r ship Aster isk," APOD's discussion forum (http://asterisk.apod.com/ viewtopic.php?f=29&t=34284&p=239152#p239156 ). Back home, I worked on processing the images and putting together the six-frame composite, which took almost as much time as my trip. Experimenting with various techniques I've used for star trails and sun and moon sequences, I settled on manually layering onto the first night's photo each successive image. Aligning the stars while keeping the comet correctly oriented proved challenging, but it was worth it. I now have a beautiful photo to go with fond memories of six cold January nights observing Lovejoy with friends. Explore more night sky photography at

www.stanhonda.com.

Submit your photography questions to

stanhonda@gmail.com.
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.


March 2015

The Amateur Astronomers' Series ­ Part 2: Optical Options for Telescopes
By Evan Schneider Hello again, amateur astronomers of the AAA! With the second article of this series, it's time to take the next step on your journey to the stars. In January, we took a look at a set of 7x50 binoculars as a way to begin observing the Moon and several planets. With this basic set of eyes, you can learn to familiarize yourself with the night sky and get a glimpse of distant objects, like the Andromeda Galaxy (M31), which is 2.2 million light-years, or thirteen thousand quadrillion miles, away. Although just a fuzzy ball of light, it can be found between the constellations Pegasus and Cassiopeia. Now, let's turn our focus to starter telescopes. If binoculars were your launch pad, a telescope will be your first orbital flight. Just as NASA takes space exploration one step at a time, you should step up your equipment in phases, giving you time to learn more about the optics behind observing. This way you can stretch your night sky knowledge before leaving orbit to explore deep space targets. There's so much to see (and perhaps photograph, someday), and a starter scope can up your astronomy game, without breaking the bank. Entry level telescopes come in several flavors, but they all gather light and deliver it to an eyepiece. Here is a review of the merits of each, in the context of first -time observing. Reflectors u se on e or a series of curved (concave) mirrors to bring an image to the eyepiece. This parabolic mirror takes the distant light of a star, which arrives to Earth as a series of parallel rays, and combines it into a single image. Other telescopes are subject to chromatic aberration, where the Reflector telescope colors of the spectrum are not properly aligned during capture, but reflectors focuses across all wavelengths of light, so no problems there. But, reflectors to have a negative side. Their optics can fall out of alignment, and the tube, which is open to the air, requires frequent maintenance to keep the inside clean and free of dust. If you're looking for less fuss for your first telescope, then this may not be your best option. Refractors a r e my p er son a l fa vor it e. I n st ea d of u sing a mirror to gather light, a refractor uses a glass lens. The first telescopes built were refractors, so there's a lot of history here. Galileo built a small, two-lens refractor to make his celestial discoveries. His legacy is felt in the continued development of this popular design. The largest refractor ever built is at the Yerkes Observatory in Williams Bay, Wisconsin. In 1897, George Ellery Hale, who went on to support the work of Edwin Hubble, persuaded a wealthy Chicago businessman to fund the 40 -inch refractor, which still operates today. The sealed tube of a refractor protects it from the elements, and images remain crisp and clear. The rugged design also prevents Refractor telescope 6 misalignment, which is critical for observing. But of course, chromatic aberration creeps in with a refractor. Color deviation distortion can create a rainbow around the image. This is acceptable for the amateur astronomer on a budget, because your first glimpse of the rings of Saturn or the cloud bands of Jupiter will be crystal clear. Al Nagler has conquered chromatic aberration with his TeleVue Optics eyepieces for higher -end refractors, bringing amateur astronomy to a new level. Reflectors and refractors were sufficient for amateur astronomers until 1930, when German optician Bernhard Schmidt had a new idea. The Schmidt telescope was catadioptric, comb in in g t h e b est of r eflectors and refractors to offer aberration-free images with a compact, sealed tube design. It was based on Laurent Cassegrain's 1672 reflector. In 1941, Dmitri Maksutov patented his Catadioptric telescope version, now known as the MatsukovCassegrain telescope. However, the shorter tube length design sacrifices some image brightness in exchange for this versatile and extremely portable telescope. If you attended the AAA Astro Answers event at AMNH in November, you were treated to a program honoring the grandfather of sidewalk astronomy, John Dobson, who passed away in 2014. His Dobsonian telescope modified the Newtonian reflector (invented by Newton in 1668), using a parabolic primary mirror and secondary flat mirror to focus light. Dobson increased the size of the primary mirror to gather the maximum amount of light possible, so distant objects would become clearer. The Dobsonian looks more like a canon than a telescope, and it rests squarely on a base on the ground, unlike most tripod-mounted telescopes. Dobsonians can get sizeable and expensive, depending upon the manufacturer and opSidewalk astronomer John tics, so you might find a used one Dobson (right) invented his popular telescope in the 1960s. to fit your budget. So, where can you go to find your first telescope? Visit Mike Peoples at Adorama in Manhattan! As AAA's strategic partner, he often speaks at StarFest events and has recommendations and discount telescopes for AAA members. Email him with your questions at michaelp@adorama.com. Purchasing new equipment is exciting, but remember that the best telescope you buy is the one you actually use. Take it out as often as you can on as many nights as possible, even just to practice setting it up. The scope not gathering dust in the closet is the scope that fits you just right!
Sources: astronomynotes.com; amazing-spacestudies.stsci.com; space.com; universetoday.com; space.about.com; astronomics.com. Evan Schneider's series seeks to encourage AAA members to find a telescope and fall in love with observational astronomy.


March 2015

Catching up with Comet Catcher Rosetta
AMNH FRONTIERS LECTURE By Richard Brounstein "L et's talk about com ets!" began Dr. Joel Parker, a member of the U.S. science team working with the European Space Agency's Rosetta spacecraft. On a freezing night in February, space lovers traversed an icy city to hear him speak at AMNH about icy Comet 67P/Churyumov­Gerasimenko and Rosetta's historic mission to that Solar System object. Centuries ago, humans knew almost nothing about comets. Ancient observers thought these ethereal objects showed up suddenly in the sky before disappearing mysteriously. Were they sent by the gods as a portent of doom, to warn of an impending plague or the death of a monarch? Unlike stars and planets, their movements seemed totally unpredictable. Now, we know their motions and orbits are, in fact, predictable. We also know where they come from. Thanks to modern astronomy and advanced spacecraft, like the Deep Impact probe, which purposely collided with Tempel 1 in 2005, we even know what they're made of. These dirty snowballs are actually icy dirtballs. They are about as dirty a place as you can find in the Solar System, and that is where ESA has sent its expensive and pristine space probe. Rosetta has made the first true rendezvous with a comet, and its companion, Philae, made the first comet landing, setting down (after a few bounces) in November. Comet 67P

was full of surprises. The Hubble Space Telescope had provided only a ESA ESA fuzzy image of Comet 67P/C-G imaged by the OSIRIS camera on Rosetta in July and August 2014 from 3,400 mi the peanut­ or (right) and 177 mi (left) away, respectively. duck-shaped object. Getting up close, Rosetta took higher resolution images and mapped 70% of the comet's surface, revealing mountains, sharp cliffs, surface cracks, and boulders. Comets date back to the early Solar System, and they have remained mostly unchanged for 4.6 billion years. There are two different types: Jupiter-family comets are bound within the orbit of Jupiter but formed in the Kuiper Belt, beyond the orbit of Neptune; while long-period comets come from the Oort Cloud, a vast area of space far at the edge of our Solar System. Every once in a while, one of these makes its way into the inner solar system. Good thing they come to us, or else we would never get a chance to study them. Scientists believe that these far-off comets may be responsible for bringing water to the planets of the inner Solar System. In every glass of water, you may be drinking a small amount of comet water. But, in order to determine if Earth's water came from a comet, we need to know if it has the same flavor. Scientists measure the water's ratio of deuterium (a hydrogen isotope) to regular hydrogen. The D/H ratio of
AMNH Frontiers Lecture (cont'd on page 8)

Probing the Universe
Dawn to Arrive at Dwarf Planet Ceres this Month On M ar 6, NASA's spacecraft Dawn will enter a fivemonth orbit around dwarf planet Ceres, the second target of its two-part mission to visit NASA Dawn took its sharpest images of dwarf large, intact protoplanplanet Ceres from 52,000 mi away in Feb. ets and learn about the early Solar System. In 2011 and 2012, it explored the giant asteroid Vesta. Both bodies formed early, in the first 10 million years of the Solar System, and reside in the Asteroid Belt between Mars and Jupiter, but they evolved differently. Vesta was discovered to be a differentiated, terrestrial world, like inner solar system bodies. Dawn found evidence of hydrated materials enriched and depleted across Vesta's dry, basaltic surface. Larger, less dense Ceres, which has water vapor in its thin atmosphere, is believed to be icy, like bodies of the outer Solar System. Just a little further from the Sun, Ceres managed to form wet and stay cool, while Vesta's accreting material melted from solar heat. Closing in on Ceres, Dawn's sharp images of the dwarf planet reveal craters and curious bright spots. "W e ex pected to be surprised; w e did not expect to be this puzzled," sa id Chr is Russell, Da wn's principal investigator. He and his team will get a closer look at these features very soon. AM W Source: nasa.gov. 7

Celestial Selection of the Month
Thor's Helmet About 12,000-22,000 light-years away in the constellation Canis Major is a bright, hot, giant star about to go supernova. A W olf-Rayet class star, WR7, is 16 times more massive than the Sun, and it is losing that mass quickly, billions of times faster than the Sun, through intensely strong stellar winds. Wolf-Rayet stars are rare and distant. They are a brief stage in the end-life of the most massive stars, occurring once they've lost most of their outer layers. Such exceptionally massive stars are rare themselves, because they form less often and have short lifespans. Wolf-Rayets continuously eject gas into space, producing an expanding envelope of nebulous gas. Surrounding WR7 is an emission nebula known as Thor's Helmet (NGC 2359). Most of its structure is a bubble formed by stellar wind, but interactions with a nearby molecular cloud are likely responsible for the curved, bow shock shape that forms the horns on the Norse god's headgear. Scientists estimate NGC 2359's age between 78,000 and 236,000 years, but they are not sure if it was created by its central star as Wolf-Rayet WR7 or as Bob and Janice Fera its predecessor, a massive red A blue-green color indicates supergiant. AM W oxygen atoms in the gas from a
Sources: wiki.com; apod.nasa.gov.
strong emission of Thor's Helmet.


March 2015

AAA Events on the Horizon
SUN, Mar 1 @ 6:00 pm Entertaining Science Series at Cornelia Street Cafe, P
"Pluto and the A rriv al of N ew Horiz ons," a lecture by AAA's Jason Kendall. Seating is limited. Tickets are only available at the door.

AMNH Frontiers Lecture (cont'd from page 7)

FRI, Mar 6 @ 6:15 pm AAA Lecture at AMNH, M Next: April 17
"Understanding Dark M atter, N eutrinos, and Inf lation w ith CM B Observations" with Neelima Sehga l in the Ka ufma nn Thea ter . (Enter 77th St)

@ 6-9 pm Observing at Sunnyside Gardens Park - Queens, PTC
This private park will be open to the public for a special observing event for all ages, with fun activities, hot drinks, and baked goods.
(Alternate date for inclement weather: SAT, Mar 7)

MON, Mar 9 @ 7:30 pm AMNH Frontiers Lecture at the Hayden Planetarium, P
"S upernov a Forensics: A S tellar Inv estigation f rom Cradle to Grav e and Beyond" with Alicia Soder ber g. Review new r esults fr om Ha r va r d's Supernova Forensics team and find out how scientists study star explosions that happen far away and long ago. (Enter 81st St)

SAT, Mar 21 @ 12 - 5 pm NASA Sun/Earth Day at the Cullman Hall of the Universe, P
Explore the special relationship between the Sun and Earth. Talk with scientists, look through telescopes, and get hands -on at AMNH.

FRI, Mar 27 @ 8 pm Columbia University Stargazing & Lecture at Pupin Hall, P
"How to B uild a Galax y " with Munier Salem. (Observing 8:30pm , C)

TUES, Mar 31 @ 6:30 pm AMNH Astronomy Live at the Hayden Planetarium, P
"O u r C osm ic A d d r ess" wit h Br ia n Ab b ot a n d AAA's C h r ist in a Pease. Hone in on Earth's position in the Solar System, Milky Way galaxy, and the observable universe. (Enter 81st St)
C: Cancelled if cloudy; M: Members only; P: Public event; T: Bring telescopes, binoculars.

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

Message from the AAA President
Hello AAA Members!
Most of you have renewed your AAA Membership for 2015, and we thank you! If you haven't done so yet, renew by mail, or online through the portal at www.adminaaa.org. You will need your member ID and password for login. Please renew as soon as possible. We hope you will also consider making a contribution to AAA with your renewal. AAA has a new website! Thanks to all our members who volunteered their time, especially Susan Andreoli and Stan Honda. Kudos on a job well done! It looks great on mobile devices too. PHOTO CALL: AAA would like to post your pics on the new website. Please send photos via email to president@aaa.org, and include a brief caption. SAVE THE DATE for the annual AAA Spring Starfest at Woodlawn Cemetery on May 2. Keep an eye out for more details to come. Lastly, don't miss the next lecture in the AAA series at AMNH when Neelima Sehgal discusses dark matter, neutrinos, and the inflationary theory of the universe on Friday, March 6. Check out the entire lecture schedule at www.aaa.org/lectures. Marcelo Cabrera AAA President

67P's water is 3 times higher than that in Earth's oceans, so it's definitely not a match. It is also higher than the D/H ratio on fellow Jupiter-family comet Hartley 2 ­ the only comet measured that does match ­ and even higher than those of long-period Oort cloud comets. With all this water and ice, one would think that comets would be bright reflective objects. Not so. Comet 67P is as dark as coal. It reflects only about 4-6% of the light it receives. Compare that with Earth, which reflects 30 -35% of light. The bright photos of 67P taken by Rosetta required long exposure times. You might also think that rocky 67P would be a dense object. Not so. It would float on an ocean like an enormous rocky iceberg. The most extraordinary achievement so far for the Rosetta mission was landing the Philae probe. Its gravity is so low (1/60,000 of Earth) that a tennis ball dropped from one meter above would take 2 full minutes to hit the ground. 100 kg Philae weighs about the same as a piece of paper on 67P. The lander had harpoons to grab the surface and hold on after contact. Philae's landing was also completely unpowered. Rosetta released Philae on a certain trajectory ­ no rocket thrusters were engaged to slow the lander or adjust its course. It relied solely on Newton's laws of gravity to land. ESA Like a slow marathon runner, it Rosetta's Philae lander. travelled 22 km in 7 hours. Philae landed right on target. Unfortunately, the harpoons to secure it onto 67P's surface failed. It bounced four times before finally getting wedged between some shady rocks. Although Philae ran out of power, blocked from sunlight, it turned out to be an opportunity in disguise. Philae's instruments now have dust samples from four different sites. Rosetta learned that 67P has surprisingly little ice on its surface. Its ice is buried up to several meters under rock. The temperature differences in the rocks are enormous. Areas only inches apart can have a temperature difference of 100 degrees Celsius. In early February, Comet 67P was far from the Sun, so there was very little outgassing. About two cups of water a second were released. In a few months, as it comes closer to the Sun, outgassing will reach 80 gallons of water a second. This will be exciting to watch, and if sunlight can reach Philae to power it up and communicate with Earth, we will get a front row seat to the action, watching a comet come to life from the surface. Here's hoping!

Eyepiece Staff
March Issue

Editor in Chief: Amy M. Wagner
Copy Editor: Rich a r d Br ou n stein
Contributing Writers: R ich ar d B r ou n st ein , Tony Faddoul, Stan Honda, Evan B. Schneider, and Amy Wagner Administrative Support: J oe Delf au sse Printing made possible by McVicker & Higginbotham

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.
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