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Journal of the Amateur Astronomers Association of New York October 2007 Volume 55 Number 10, ISSN 0146-7662

EYEPIECE

City Stargazers Can Pierce the Glare to Glean Wonders
By John Delaney
At a recent gathering of college friends in Vermont, I spent a lot of time marveling at a spectacle that's become quite a rarity for me in 10 years as a city dweller: a clear night sky. Fantastic, but also a bit disorienting. I almost didn't recognize the Summer Triangle with the jarring distraction of the Milky Way running through it, so foreign to my eyes was a profusion of stars.
It strikes me (and others) as somewhat odd that I've become a full-fledged stargazer in New York City, perhaps the worst place for seeing and appreciating the beauty of the night sky. Only the brightest objects can cut through the glare, and finding a place to gaze upwards is tricky with so much diversion on the ground. While city residents can be especially picky about how to spend their time, watchers of the skies have learned to make do with less. We have come to appreciate and learn more about what you can see despite light pollution. I've always had an interest in astronomy, but it wasn't until I started hearing and reading about the historic perihelic opposition of Mars in 2003 that I became an active observer. I was hooked by a big colorful ad for a 6 -inch, F8 reflecting telescope on a equatorial mount in Sky & Telescope, which implor ed the potentia l buyer to seize the opportunity to see Mars. My former living quarters--a room on Central Park West overlooking trees and the eastern sky--also solidified my new avocation. I could simply open the window and point the instrument through the opening. In the weeks before the appearance of Mars, viewing the Moon at 120x magnification was an exhilarating experience. When Mars appeared, I viewed it for about an hour every clear night, enough time to experiment with various fil-

ters to tease out the southern polar cap and prominent features like Syrtis Major and Hellas. And, when one observes from the comfort of one's living space, one can listen to Gustav Holst's "The Planets" and observe maps of Mars on the Internet. But the living arrangement didn't last, and I may never know such convenience again.
Other bright objects became sources of discovery. Solar observation was next, first with a projection plate, then solar filter. This skill came in handy for the 2004 transit of Venus, when I lugged both of my scopes to Carl Schurz Park. It was quite an effort, but I figured that if Captain Cook could travel to Tahiti for such an event, I could get out of bed at 4 a.m. and manage a 10-block cab City Stargazers continued on page 12

Annual Starfest is November
The AAA, in conjunction with the Urban Park Rangers, will present its annual Urban Starfest in the Central Park Sheep Meadow Saturday, November 10 from 6:30 to 10 p.m. Rain date is the following evening. The main attraction, and why Starfest is later this year, is Mars. It will reach opposition on Christmas Eve, when it will be closest to Earth and up all night. While Mars won't be as big or bright November 10, we should be able to see its polar ice cap and other markings. Early in the evening, the Summer Triangle of the bright stars Vega, Altair and Deneb will be prominent. The Ring Nebula, beautiful double star Albireo and the Andromeda Galaxy will be among our scopes' targets. By 9 p.m., the winter stars will have risen, and we will see the Pleiades and Hyades, two beautiful star clusters. Coming into view will be the famed Orion Nebula.


What's Up
By Tony Hoffman The Sky for October 2007
The Ascent of Mars. O ver t h e p a st few m on t h s, Mars has steadily brightened, but few have seen it as it's been confined to the morning sky. Now, though, it rises before midnight and spends the month in Gemini. By month's end, Mars will blaze at magnitude -0.6. Its gibbous disk will then be 12 arc-seconds wide, large enough to reveal dark markings. Syrtis Major, Mars' most prominent feature, will face Earth around midnight late in the month. Orionid Meteor Shower. T h e M oon will b e ou t of the way on the morning of October 21, when the Orionid meteor shower is due to peak. Rates can reach 20 or more per hour near maximum. Orionid meteors, debris left behind by Halley's Comet, are very fast and often leave persistent trains. Moon Occults the Pleiades. W h en t h e b r igh t Moon, a day past full, rises at dusk on October 27, it will lie amid the Pleiades star cluster. Because of the Moon's brightness, low altitude, and sky brightness, you'll need a telescope to observe this event. The Moon will occult Alcyone and a number of fainter stars. October 2 October 3 Moon lies near Mars. Last-quarter Moon at 6:06 a.m.; Mars lies

On the morning of October 7, Regulus, Saturn, Venus and the Moon will take part in a spectacular conjunction. near open cluster M35. Moon lies near Venus. Moon lies near Regulus and Saturn. Draconid meteor shower peaks; Venus lies near Regulus. New Moon at 1:01 p. m. Ven u s lies n ea r Sa t u r n ; M oon lies n ea r Antares. Moon lies near Jupiter. First-quarter Moon at 4:33 a.m. Orionid meteor shower peaks. Moon at perigee, 221,676 miles from Earth, 7:51 a.m.; full Moon at 12:52 a.m. Moon occults the Pleiades. Venus at greatest elongation in morning sky. Moon lies near Mars.

October 6 October 7 October 9 Octcber 11 October 15 October October October October 16 19 21 26

October 27 October 28 October 30

Less than Perfect View of Perseid Meteors and Lunar Eclipse
By Joseph A. Fedrick
I went to Inwood Hill Park August 11 to see the Perseids. Jupiter came out almost immediately after sunset. Jupiter revealed a dark, well-defined North Equatorial Belt and a faint, blotchy South Equatorial Belt. The M22 globular cluster in Sagittarius was barely visible in the haze near the horizon. The M13 globular cluster in Hercules was easier to find with the 3-inch telescope and appeared as a round, fuzzy, slightly granular patch of light. The Ring Nebula in Lyra looked like a ghostly glowing smoke ring in the same scope. The double star Alberio in Cygnus was spectacular with topaz
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yellow and sapphire blue stars. The double cluster in Perseus also looked spectacular, like two close groups of sparkling diamonds. However no meteors were visible that night. I saw ruddy Mars already rising approximately 5 degrees almost directly below the Pleiades. Two nights later, I saw one reddish bright meteor crossing Orion just before dawn; it might have been a Perseid. On the morning of August 28, I saw a partially eclipsed Moon looking like a crescent moon near the west horizon. A crescent moon normally appears in the east in the morning. The Moon was entering Earth's Perseid Meteors continued on page 6


A Message from AAA President Richard Rosenberg
Hello, members: One benefit of being AAA president is meeting well-known astronomers I've long admired. Recently, out of the blue, I received an e-mail from Jay Pasachoff, professor at Williams College and author or co-author of a number of astronomy books including one of my favorites, the Peterson Field Guide to S tars and Planets. Jay, an AAA member from 1956 to 1959, recently visited Pulkovo Observatory near St. Petersburg, Russia, and noticed in its museum the Amateur Astronomers Medal we awarded the observatory! He took photos of the award as well as the famous large refractor and main observatory and sent copies to us. They're now in the gallery of our website.

Since he was in town the weekend following Rosh Hashanah, Tom Haeberle and I met him for breakfast. We had a fine time discussing the AAA then and now, eclipses (Jay had just returned from a solar eclipse in South America) and other astronomical topics.
Jay participated in the Moonwatch program 50 years ago as a 14-year-old. Members of the AAA gathered at the roof of the RCA building before sunrise to see if they could spot Sputnik, the first man -made satellite, just launched, and help determine its orbit. Jay is preparing a talk on Moonwatch, so if any of you were involved, or know people who were, he'd like you to contact him: Jay.M.Pasachoff@williams.edu or 33 Lab Campus Drive, Williamstown, MA 01267. I hope Jay will speak at our 2008-09 lecture series, and you all will have a chance to meet him.

Rich Rosenberg, AAA President, pr esident @a a a .or g, (718) 522-5014

Talk on the Hubble Will Begin AAA's '07-'08 Lecture Series
Dr. Mario Livio, senior astrophysicist and head of the Office of Public Outreach at the Space Telescope Science Institute (STScI), Baltimore, will open the AAA's 2007-08 lecture series when he discusses "Achievements of the Hubble Space Telescope" on Friday, October 5. The free public lecture is at 6:15 p. m. in the Kaufmann Auditorium of the American Museum of Natural History. Livio's talk will be the AAA's annual John Marshall Memorial Lecture. Marshall, who served as president and executive director of the club, is considered a seminal figure in the AAA's growth. He died in 1997. Livio joined STScI, which conducts Hubble's scientific program, in 1991. Livio has done much fundamental work on accretion of mass onto black holes, neutron stars and white dwarfs, as well as on the formation of black holes and the possibility of extracting energy from them. In recent years, Livio's research has focused on supernova explosions and their use in cosmology to determine the rate of expansion of the universe, and the nature of dark energy. The 2007-08 AAA lecture series will feature these other speakers: November 2: Laurence Marschall, Gettysburg College, "Pluto Deconstructed"; December 7: Michael Allison, Goddard Institute for Space Studies, "Planetary Time and Seasons--Space Clocks and Extraterrestrial Climates"; January 4, Jerry Bonnell, NASA, "Astronomy Picture of the Day"; February 1: Nergis Mavalvala, MIT, "Detecting Gravitational Waves: LIGO and the Search for the Elusive Wave"; March 7: Arlin Crotts, Columbia University, "Liquid Mirror Telescopes Are Looking Up"; April 11: Eric Myers, LIGO Hanford Observatory, "Searching for Ripples in Space-Time with your Home Computer."; May 2: Eric Gotthelf, Columbia University, "Juvenile Neutron Stars and their Outbursts."
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AMNH, Others Shed New Light on Planet Formation
A new computer-modeled theory shows how rocky boulders around infant stars team up to form planets without falling into stars. The modeling was developed by astrophysicists from the American Museum of Natural History, the Max Planck Institute for Astronomy in Heidelberg, the University of Virginia and the University of Toronto. Efforts to understand how planets form have been stymied by a fundamental question: How can large boulders avoid being swept into the central star by the effects of gas surrounding the star or being pulverized by other objects before gravity can bind them into asteroid-size planetesimals too big for gas to influence or collisions to destroy? Planets are believed to form from the collision and accretion of smaller planetesimal bodies. The research sheds new light on this fundamental part of the planet-forming process and shows that the forces that appear to prevent planetesimals' formation-gas drag and turbulence--can actually promote it. In early stages of planet formation, dust grains in the diffuse cloud surrounding a young star collide and stick together to build up ever-larger bodies. Earlier planet-formation models showed the slower-rotating gas disk surrounding the central star appeared to impart a drag on boulders larger than a few feet in diameter, causing them to slow and spiral into the star after only a few hundred orbits. In addition, fast-moving boulders don't stick together well but collide violently and break apart. The planet-formation process, first shown more than 30 years ago, said that boulders tend to fall into a star in a celestial blink of an eye. Some mechanism had to be found that prevents them from being dragged into a star. The answer came from recent studies of boulders moving through gas that showed two effects. First, turbulence in the gas causes them to clump in high -pressure regions. Second, gas drag causes further clumping as boulders in the densest regions start pulling gas and nearby debris with them. When the team included this behavior in simulations of gas and gravitationally interacting boulders, they found orbiting boulders concentrated so strongly that gravitational attraction between boulders
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caused them to collapse into large planetesimals unaffected by gas drag. Therefore, many boulders can join to fight a cosmic headwind that otherwise would doom them. Over time, dust particles in an accretion disk bunch together and form large boulders, but eventually they meet resistance from the disk's mist of gas that drags them into the star. But modeling the turbulence within the gas showed that boulders can team up and form planets. "Turbulence in the disk concentrates boulders in regions of higher pressure," says Mordecai-Marc Mac Low, curator and chair of the AMNH's Department of Astrophysics. Such disturbance is enough to enable boulders to fight the dooming headwind. "If the gas is sped up, the boulders don't see a headwind. By getting the gas going with them, they conserve energy and stay in orbit. Enough boulders gather together, gravity takes over and they collapse into planet-like bodies," Mac Low says. Although Mac Low and his colleagues kept planetforming boulders safe from the gravitational clutches of stars in their simulation, he notes that many questions remain. "There are enough uncertainties that [planet formation] isn't going to be an open-and-shut case any time soon. We don't know how that collapse into a planet actually occurs. You've got thousands, millions of boulders swarming together. In my nightmares I imagine that they grind each other down to dust and it all goes away." Despite the problem, Mac Low is confident the theory will hold up to scrutiny. "All that material is gravitationally bound together, so we think it's likely it will form large objects." Running the computer simulation, in fact, formed tight boulder clusters as large as the dwarf planet Ceres. How giant planets form is another question. One idea is that gas coalesces around a rocky planet. "Of course, this work raises new questions about how planet formation occurs in protoplanetary disks. Still, we believe the fundamental properties of gasboulder interactions we describe will provide the ultimate solution to this longstanding problem. Our work provides the first scenario that appears capable of answering this gap in our basic understanding of planet formation."


Review: The Exciting, Varied Search for Extrasolar Planets
By Thomas Haeberle
The discovery and study of extrasolar planets hold the promise of finding life on other worlds and may be key to understanding how our solar system formed. In the solid "The New Worlds: Extrasolar Planets," Fabienne Casoli and ThИrХse Encrenaz provide plenty of color illustrations, graphs and charts, giving the feel of a textbook. Their book (Springer Praxis Books, $29.95) is a translation of the original (but updated) French version. The book attempts to answer whether our solar system is common or unique. Why is ours so stable while in other star systems chaos reigns, with giant planets migrating inwards? There's a need to understand why "cessation of planetary migration stops at a short distance from the star. There must be an effective mechanism at work or there wouldn't be so many planets detected." Our observations may be biased because shorter orbital periods are easier to detect.

The authors first look at early searches for extrasolar planets: the first failures, the first discoveries and observational techniques. In 1964, Piet van de Kamp announced finding planets orbiting Barnard's star, a small red dwarf some eight light-years away. Using the astrometric method, van de Kamp recorded wobbles in the star's motion for 20 years. Although his planets were disproved, van de Kamp was a pioneer in planet hunting.
In 1995, the velocimetric or radial-velocity method bore fruit in extrasolar-planet discovery. By studying shifts in the absorption lines in the stellar spectra, an astronomer can deduce a star has an unseen companion. Although this method has discovered a majority of the exoplanets, it has its limitations, such as being "suited to the study of massive, short-period planets close to the parent star. The main factor against the discovery of `outer' (more distant) planets is that the duration of the study should be at least equal to its orbital period." Another method transit method. The greater the chance it disk. This method is the transiting object mass. used in exoplanet detection is the nearer the planet to its star, the will be seen crossing the stellar an improvement since the size of can be ascertained, not just the

The Holy Grail will be to find Earth-like planets, particularly those that indicate the presence of life. Testing possible methods to be used, the Galileo spacecraft studied Earth's spectrum in the near infrared. Besides detecting water and carbon dioxide signatures in the readings, there was "the unambiguous presence of ozone and methane." Methane is a good indicator for life; "it can persist in the Earth's atmosphere only by being constantly renewed." Observing exoplanets will require using the transit or the microlensing methods.
Using our solar system as a model, the book examines a wide range of extrasolar planetary systems discovered during the past decade and looks to what we can learn about these planets. Another important field of research besides the search for life is planetary formation. Future projects in the search for new worlds and many space missions will include these objectives. The Atacama Large Millimeter Array is a new generation of giant ground-based telescopes. It will be in service in 2010, with 50 telescopes studying planetary formation. The Europeans launched the Convection Rotation and Planetary Transits (COROT) satellite in 2006 to study exoplanet transits of 12,000 stars. In 2008, NASA will launch Kepler, a space telescope that works the same way as COROT, but which will be able to detect the first Earth-sized planets in habitable zones around stars similar to the Sun. Advanced missions to follow will be Europe's Darwin and NASA's Terrestrial Planet Finder missions. Both will involve multiple telescopes in space to achieve unprecedented angular resolution of exoplanets. "Given the similar challenges involved...the two projects may fuse into one, which could be ready by 2020."
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A fourth technique is based upon an "application of Einstein's theory of general relativity, according to which light rays are bent in the vicinity of very massive objects." Four planets have been found this way, yielding one six times the mass of Earth. "Through a careful survey of compact star fields, a temporary increase in brightness of a faint star [indicates that] the unseen companion is crossing the line of sight; this is the gravitational microlens effect."


Review: Three Useful New Astronomy Books
Two new books discuss astronomy with a broad sweep. They're "The Handbook of Astronomy" by Clare Gibson, from Barnes & Noble Publishing, in arrangement with British firm D&S Books Ltd. ($7.98), and "Astronomy: The Definitive Guide to the Universe" by Duncan John, from Parragon Publishing in Britain ($19.98). The John book is more impressive as to completeness, up-to-the-minute content, and impressive photos and other artwork. It also has a clearer table of contents and impressive charts on the solar system. Each book, however, offers a solid range of information for amateur astronomers seeking to broaden their knowledge. Also useful in that regard is "The 50 Best Sights in Astronomy and How to See Them: Observing Eclipses, Bright Comets, Meteor Showers, and Other Celestial Perseid Meteors continued from page 2 Wonders" (Wiley, $19.95, paper) by Fred Schaaf. The author, well-known to many for his columns in S k y & Telescope, not to mention other books, deter mined the order in which the sights are discussed by width of field of view necessary to enjoy the sight best. The order is from the widest to the narrowest view: 180 degrees (the whole sky) to 100 degrees (naked-eye scan); 100 degrees to 50 degrees (the widest fixed nakedeye field); 50 degrees to 15 degrees (moderately wide naked-eye field); 15 degrees to 1 degree (narrow nakedeye field, binoculars field and wide telescopic field); and 1 degree to 0.1 degree or less (medium-to-narrow telescopic field). There are useful appendices and a glossary. The writing is clear and informative, although I wish there had been more than 11 color photos--a cost consideration, I assume. ­ Dan Harrison

Custer Seeks Help on Exoplanets
The Custer Institute in Southold, N. Y., is embarking on an extensive search for exoplanets. Team members have obtained encouraging results from preliminary testing. They captured the transit of HD-189733, a Jupitersized exoplanet near M27 (Dumbbell Nebula), and achieved millimagnitude light-curve accuracy. These data provided information needed to extrapolate noise level, sensitivity and other variables. More data is required and help is needed. Participants will need a good CCD camera, at least an 8-inch telescope and imaging experience. The task: take highquality images of specified areas of the sky. While equipment will work the entire time, participants will only be required to set up and periodically check it. To sign up: katz@scientific-consultants.com.

shadow. The shadow was quite dark, allowing no view of the lunar maria or craters as I viewed with a 7x50 pair of binoculars. In the opposite direction from the Moon, rising in the east, was Venus. During the first two weeks of September, Jupiter dipped lower in the southwest each evening and major changes in the Jovian cloud belts continued. Orion appeared higher in the sky each morning. By September 12 I had seen Saturn reappear in the morning far below Venus. The rings were at a shallow angle, more nearly edge -on than in recent years as seen at 50x in my 60mm refractor. Venus was a dazzling thin crescent.

Corrections
Last month's book review of "The Telescope: Its History, Technology, and Future" misspelled the last name of the author. He is Geoff Andersen, not Anderson. And we apologize for anyone who was inconvenienced by the wrong date for the Recent Advances in Astronomy seminar in the Events on the Horizon column. It was Thursday, September 20, not Tuesday.
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Apollo Astronaut Documentary
A new documentary tells the human stories of the Apollo astronauts, from when we sent men around the Moon during the 1968 flight of Apollo 8 through six more landings, to 1972 (Apollo 17), and the aborted Apollo 13. "In the Shadow of the Moon" was filmed with the aid of "Apollo 13" director Ron Howard.


Tyson Explains Why the U. S. Needs to Explore Space
Hayden Planetarium director Neil deGrasse Tyson wrote the cover story in the August 5 P a r a de on "Why America Needs to Explore Space." Excerpts: [The U. S.'} ambitious investment in science and technology drove a half-century of unprecedented wealth and prosperity that we take for granted. Now, as our interest in science wanes, America is poised to fall behind the rest of the industrialized world in every measure of technological proficiency. tumors in mammograms. The medical community adopted new techniques being used for the Hubble to assist early detection of breast cancer. Countless women are alive today because of ideas stimulated by a design flaw in the Hubble Space Telescope. You cannot script these kinds of outcomes, yet they occur daily. The cross-pollination of disciplines almost always creates innovation and discovery. And nothing accomplishes this like space exploration, which draws from the ranks of astrophysicists, biologists, physiologists, chemists, engineers and planetary geologists. Their collective efforts have the capacity to improve and enhance all that we value as a modern society. How many times have we heard: "Why are we spending billions of dollars in space when we have pressing problems on Earth?" Let's re-ask the question: "What is the total cost in taxes of all spaceborne telescopes, planetary probes, the rovers on Mars, the space station and shuttle, telescopes yet to orbit and missions yet to fly?" Answer: less than 1% on the tax dollar-7/10ths of a penny, to be exact. I'd prefer that it were more, perhaps 2 cents on the dollar. Even during the Apollo era, peak NASA spending amounted to no more than 4 cents on the tax dollar. At that level, NASA's current space-exploration program would reclaim our preeminence in a field we pioneered. Right now, the program paddles along slowly, with barely enough support to ever lead the journey. So, with 99 out of 100 cents going to fund the rest of our nation's priorities, the space program is not now (nor has it ever really been) in anybody's way. Instead, America's former investments in aerospace have shaped our discovery-infused culture in ways that are obvious to the world. We are a sufficiently wealthy nation to embrace this investment for tomorrow--to drive our economy, our ambitions and, above all, our dreams.

Science and technology are the greatest engines of economic growth the world has ever seen. Without regenerating interest in these fields, the comfortable lifestyle to which Americans have become accustomed will draw to a rapid close.
In October 2003, China became the third spacefaring nation. Next step, the Moon. Meanwhile, Europe and India are redoubling their efforts to conduct robotic science on spaceborne platforms. There's also growing interest in space exploration from a dozen other countries. This emerging community of nations is hungry for a slice of the aerospace universe. In America, contrary to our self-image, we are no longer leaders but simply players. We've moved backward just by standing still. The greatest explorer today is not even human. It's the Hubble Space Telescope, which for nearly two decades has offered us all a mind-expanding window to the cosmos. But when the Hubble was launched in 1990, a blunder in the design of its optics generated hopelessly blurred images. Corrective optics were installed during the telescope's first servicing mission in 1993, which enabled the sharp images we now take for granted. But for three years the images were fuzzy. What to do? We kept taking data, hoping some useful science would nonetheless come of it. Eager astrophysicists wrote suites of advanced image-processing software to help identify and isolate stars in otherwise crowded, unfocused fields. These novel techniques allowed some science to get done while the repair mission was planned. Meanwhile, medical researchers at the Georgetown University Medical Center in Washington, D.C., recognized that the challenge faced by astrophysicists was similar to that faced by doctors in their visual search for

Connolly Takes Louisville Post
Rachel Berger Connolly, former astrophysics education manager at the AMNH's Rose Center for Earth and Space, has accepted a position at the University of Louisville as professor of science education and director of the university's Rauch Planetarium.
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Briefs: Universe Has 6 Billion Trillion Miles of Emptiness
Astronomers have found a tremendous hole in the universe 1 billion light-years across or nearly 6 billion trillion miles long. It has no stars, no galaxies, no black holes, not even dark matter. Such patches in the universe have long been known, but this is far bigger than ever imagined. Observations of cosmic microwave background radiation showed a cold spot empty of matter. There's a remarkable drop in the number of galaxies in a region of sky in the constellation Eridanus. The void is 5 -billion-to-10-billion light-years away. Holes in the universe probably occur when gravity from areas with bigger mass pull matter from less-dense areas. Astronomers have spotted a planet that's survived the massive ballooning of its parent star, providing the first optimistic evidence for the long-term survival of Earth. The discovery could spur searches for similar redgiant survivors and answer whether Earth will survive the Sun's swelling when it becomes a red giant in a few billion years. The parent star, V 391 Pegasi, belongs to a rare class of red giants, B-type subdwarfs, that have prematurely expelled their outer shells of hydrogen. For reasons unclear, V 391 Pegasi expelled its outer envelope early, before the core even began fusing helium, exposing a compact, dense star that hasn't fully died. More unusual, V 391 Pegasi pulsates, dimming and brightening for several minutes at a time. This is the first planet found after the red-giant phase of its star. The planet is about three times the mass of Jupiter and orbits its star from a distance of some 158 million miles. Scientists think that during the star's red-giant phase, only about 1 AU separated star and planet. The planet's presence may relate to V 391 Pegasi's premature shell ejection. Some crucial ingredients for life on Earth may have formed in interstellar space rather than on Earth's surface. Computer modeling indicates clouds of adenine molecules, a basic component of DNA, can form and survive the harsh conditions of space, and possibly sprinkle onto planets as the stars they orbit travel through a galaxy. Using computer simulations of space, scientists found that hydrogen cyanide gas can build adenine. Einstein's predicted warping of space-time has been discovered around neutron stars, the universe's densest observable matter. The warping shows up as smeared
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lines of iron gas whipping around the stars. The finding indicates neutron stars can't exceed 20.5 miles across. Astronomers surveyed three neutron-star binaries. They also studied the spectral lines from hot-iron atoms that whirl around in a disk just beyond the neutron stars' surfaces at up to 40% light speed. Normally, the spectral line for superheated iron atoms would show up as a symmetrical peak. But results showed a skewed peak indicating distortion due to relativistic effects. Very fast motion of the gas and related powerful gravity cause the line to smear, shifting it to longer wavelengths. The measurements allowed determination of maximum star size. Astronomers using Swift have detected a neutron star 250-to-1,000 light-years away in Ursa Minor, the closest neutron star known. It's only the eighth known isolated neutron star, one without supernova remnants, binary companions or radio pulsations. It's an unusual example of a known type of neutron star or some new type of neutron star. Its location high above the plane of the Milky Way is a mystery, but researchers think it's the remnant of a star before it exploded as a supernova.

Tiny meteors, typically no larger than a grain of sand, frequently bore hot tunnels through Earth's air to leave behind thin, glowing trails of gas sometimes seen as "shooting stars." The trails were estimated to be narrower than a meter, but until now, more precise measurements were impossible. Meteor trails begin about 75 miles above Earth, an area not usually focused on by ground telescopes or satellites. Astronomers discovered streaks can be as thin as a few millimeters across. This is the first time a meteor track's width has been precisely measured solely using light emitted.
Astronomers have found nine of the faintest, tiniest and most compact galaxies ever seen, hundreds to thousands of times smaller and vastly younger than the Milky Way. This supports a theory that hundreds of tiny galaxies merge and form larger bodies of stars. The galaxies' small mass, observed by Hubble and confirmed by Spitzer, shows they're some of the smallest building blocks of the universe, aside from stars. The scopes saw light emitted from the galaxies only 1 billion years after Briefs continued on page 9


Briefs: Star Images Called Much Sharper than Hubble's
Continued from page 8 the Big Bang. Three galaxies are stretched into tadpolelike forms rather than a rounded-blob typical of the youngest galaxies. This may signal their first fusion with neighboring galaxies to form larger, cohesive structures. Mysterious waves that help thrust solar energy into space have been detected. Researchers hope discovery of the ripples--Alfven waves--will shed light on other phenomena such as the Sun's magnetic fields and its super-hot corona. Alfven waves run along the Sun's magnetic field lines and reach deep into space. While astrophysicists have identified the waves far from the Sun, they've never been detected close to it; the ripples were too small and fast to spot. To observe the waves, scientists looked at the corona. Thanks to an imaging speed of one picture every 15 seconds, they captured the waves traveling at about 9 million mph. The waves might help explain how energy is transferred to the corona, which is millions of degrees hotter than the Sun's surface. Two space rocks in the solar system's outer asteroid belt might contain evidence for a new class of asteroids or long eroded mini-worlds. The asteroids contain basalt, which forms much of the Earth's crust and other inner planets. Basalt has also been found in space rocks shed by Vesta. This proves that an object was once large enough to sustain internal heating. Until recently, asteroids with basalt were thought to be fragments of Vesta. Astronomers claim to have taken pictures of stars twice as sharp as Hubble's. The new system takes pictures at 20 frames/second, chooses the best of tens of thousands of images, merges them together and eliminates random noise. The estimated cost is $100,000, less than a hundredth of a percent of the Hubble. The system was tested with a 200-inch telescope at Palomar. The observatory normally produces images 10 times less detailed than Hubble's, but the new camera created images twice as sharp. But Hubble can better take longer exposures and produce deeper views. The new system's most effective use may be in larger telescopes, where it can be used to expand the search for dark matter. An ancient collision between two mega-asteroids spawned the killer space rock that slammed into Earth and marked the beginning of the end for the dinosaurs, a study claims. Scientists think the collision took place some 160 million years ago in the asteroid belt between Mars' and Jupiter's orbits, and hurled large chunks of debris into space. One fragment apparently crashed into Earth 65 million years ago to form Mexico's Chicxulub crater. Another likely carved the Tycho Crater on the Moon. The study says an object 37 miles wide collided with a 106-mile-wide body in the inner asteroid belt. Wobbles in the rotation of Mars swung the planet into about 40 extreme ice ages in the past 5 million years and allowed thick ice layers to remain far away from the poles. In recent years, orbiting probes have found evidence for vast sheets of underground ice near the equator. How ice ended there remains a mystery. The answer could be in Mars' wobble. Due to Mars' lack of a stabilizing moon, its tilt can wobble as much as 10 degrees from the current 25-degree angle. While not topsy-turvy, the wobbles change the amount of sunlight reaching Mars and can cause vast amounts of ice to shift between the poles and the rest of Mars every 120,000 years. A dead, spinning star has been found feeding on its stellar companion, whittling it down to an object smaller than some planets. The pulsar has eaten away the star's outer envelope; all that remains is its helium-rich core. The system was discovered towards the Milky Way galactic center in Sagittarius. The smaller companion orbits its parasitic companion from only 230,000 miles. Its estimated minimum mass is only seven times Jupiter's. Scientists don't consider the object a planet because of how it formed. It's essentially a white dwarf that has been whittled down to a planetary mass. Scientists think that several billion years ago, the system consisted of a very massive star and a smaller star one-to-three times the Sun's mass. The bigger star evolved quickly and exploded as a supernova, leaving behind a spinning stellar corpse known as a neutron star. Meanwhile, the smaller star also began to evolve, eventually puffing up into a red giant whose outer envelope encapsulated the neutron star. This caused the two stars to draw closer together. The world's largest digital camera has been installed on a new telescope designed to seek potentially dangerous asteroids. It's on a scope in Maui, the first of Continued on page 10
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Briefs: Largest Digital Camera Will Aid Asteroid Search
Continued from page 9 four being built for the Panoramic Survey Telescope and Rapid Response System. Starting in 2010, when all scopes are completed, the project will image the sky visible from Hawaii three times per month. Objects 100 times fainter than current surveys will be seen, including 99% of asteroids 300 meters or larger that approach Earth's orbit. NASA is expected to have found 90% of objects 1 kilometer or larger near Earth by 2008. Smaller objects have been less surveyed. Being more numerous, they're more likely to hit Earth. Congress asked NASA to identify 90% of objects down to 140 meters across by 2020, but NASA says it lacks the money. Scientists revised Saturn's rotation period to 10 hours, 32 minutes, 35 seconds, 15 minutes shorter than an estimate last year. Those minutes could affect how scientists think about Saturn and other gas giants. If the new rate is correct, Saturn's winds blow slower than previously thought and instead of in a single direction, can blow east and west. The finding could also show how gas giants form and reveal more about Saturn's interior. Scientists pored over photos from Cassini's closest flyby with Iapetus, which show the Saturn moon's contrasting halves and strange mountain range in great detail. The photos were taken only 1,000 miles from the surface. Close-ups show a white hemisphere resembling snow and a second as black as tar. They also show the mountain ridge 12 miles high along Iapetus' equator. A proposed NASA mission to study dark energy should be first in its Beyond Einstein program to be developed and launched, the National Research Council urged. It noted the mission is already in prototype phase and will need less development than other missions. Martian water might have been blown into space long ago by strong gusts of solar winds, new satellite observations suggest. The findings also show solar flares erupting on the far side of the Sun can still affect the space weather of Earth. Data collected at Mars have shown higher than average amounts of oxygen ions leaking into space. If this occurred regularly over billions of years, it could account for Mars' missing water.
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The Mars Opportunity Rover took the plunge into Victoria Crater for a multi-week investigation. It was set to enter into the crater in late June when dust storms broke out and threatened to cut off sunlight to its solar cells. The rover's first destination inside the 2,400-footwide crater: a bright layer of exposed rock that might yield clues of interaction between atmosphere and surface millions of years ago. The Spirit Rover climbed atop a rock plateau dubbed Home Plate, a long-time destination. Both rovers will monitor the atmosphere using instruments initially designed to examine rocks and boulders. The instruments will measure argon, responsible for mixing the thin air between summer and winter. Proposals for a Mars sample return mission appear to be on the front burner again, but not without dispute. While many NASA scientists are pro-sample return, others worry such a mission, possibly costing $3 billion-$4 billion, would suck up money for most Mars missions in the next decade and disrupt NASA's ability to send at least one robotic mission there every two years. Spitzer has revealed a dusty star system being soaked with water vapor. The water, pulled from gassy stellar leftovers into a dusty disk, provides what may be the first direct look at how water makes its way into planets. The disk is akin to what forms around many stars and, for the Sun, yielded planets. Water in the newly observed disk, 1,000 light-years away in Perseus, is thought to equal more than five times all Earth's oceans. The young star system still grows inside a cooled cocoon of gas and dust. Ice is falling from the cocoon into a warm disk of potential planet-forming materials circling the star. As ice hits the dust, it vaporizes. The second partial solar eclipse of 2007 took place September 11. The Moon appeared to cross in front of the Sun. The Moon's outer shadow, the penumbra, sliced into the lower two-thirds of South America and part of

New Staten Island Chair
Larry Ventura is stepping down as AAA's Staten Island chair. For more than four years, Larry has done a fine job running our observing sessions at Great Kills Gateway National Park and handling inquiries from members. He'll be succeeded by Joe DiNapoli.


Events on the Horizon October 2007
M: members; P: open to the public; T: bring your telescopes, binoculars, etc.; C: cancelled if cloudy; HQ: at AAA headquarters, 1010 Park Avenue (between 84th and 85th streets); AMNH: For ticket information, call (212) 769-5200 Check the AMNH's website at www.amnh.org for an additional listing of other events. Tuesday, October 2, dusk to 10 p. m. Observing at Cadman Plaza, Brooklyn, P, T, C Model airplane flying field. Next date: November 16 Friday, October 19, 6:30 to 8 p. m. Observing at Robert F. Wagner Jr. Park at Battery Park City, P, T, C Friday, October 19, 7 p. m. Planetary Society event, N. Y. Academy of Sciences, 7 World Trade Center, 250 Greenwich St., Manhattan Neil deGrasse Tyson and Bill Nye the Science Guy will discuss "Planetary Citizenship in the Next Space Age." Tickets: http://planetary.org/programs/projects/ space_information/ny07.html or (626)793-5100. Friday, October 19 and Saturday, October 20 Astronomy Jamboree, Custer Institute, Southold, NY Info: www.CusterObservatory.org. Saturday, October 20, dusk Stargazing, Great Kills, Staten Island, P, T, C Next date: November 17 Saturday, October 27, 10 a. m. to noon Central Park solar observing, P, C At the Conservatory Waters. Next date: November 17 Saturday, October 27, 1 to 4 p. m. M, HQ Observers Group. Next date: November 17

Friday, October 5, 6:15 p. m., P AAA's annual John Marshall Memorial Lecture, P Mario Livio of the Space Telescope Science Institute will discuss "Achievements of the Hubble Space Telescope." At the AMNH's Kaufmann Theater.
Saturday, October 6, 6:30 to 8:30 p. m., dusk Upper Manhattan Observing, P, T, C Inwood Park, 218th Street and Indian Road. Next date: November 10 Saturdays, October 6 and 13 Observing at Anthony Wayne Recreational Area near Bear Mountain, dusk to 3 a. m., P, T, C For directions, aaa.org. Next dates: November 3, 10, 17 Thursday, October 11 Recent Advances in Astronomy Seminar, M, HQ Next date: November 8 Monday, October 15, 7:30 p. m. Hayden Planetarium lecture, P, AMNH Adam Riess of Johns Hopkins will discuss dark energy. Friday, October 19, 8 to 10 p. m. Observing at Floyd Bennett Field, Brooklyn, P, T, C

Contacting the AAA
If you want to join, volunteer your time, participate in events, have a question or need to change your address, e-mail secretary @aaa.org, or leave a message at AAA hq: (212) 535-2922. Also, visit us on the web at www.aaa.org. If you're interested in writing an article for Ey epiece, contact editor Dan Harrison at editor@aaa.org or (914) 762-0358.

Book on Amateur Astronomers
"Science Educators Under the Stars: Amateur Astronomers Engaged in Education and Public Outreach," just out, covers amateur astronomers' role in communicating "knowledge and passion" about astronomy to the public. It's published by the Astronomical Society of the Pacific as a 124-page paperback for $10 plus postage. The book's available at www.astrosociety.org/aspbook.html (product number BO 432). .
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City Stargazers continued from page 1 ride. It was a rewarding experience, but my attempts at photographing the event were largely foiled by the long lines of people eager to observe the spectacle through the big reflector, and who was I to turn them away? As for objects outside our solar system, I learned more about the major stars one could see, simply because on many nights, one can rarely see anything else. The brightest stars soon became objects of study, not just their characteristics but their places in mythology and popular culture. For instance, Mizar and Alcor--the apparent double star in the bend of the Big Dipper's handle-were regarded by the Arabs as an indication of good eyesight for those who could make out the "horse and rider." Arcturus, a star just passing through our galaxy that will fade from naked-eye visibility in the next halfmillion years, played a key role in helping light the 1933 Chicago World's Fair, when light from the star was focused on a photocell that switched on the floodlights. Deep-sky objects are the rarest objects for the urban dweller, but a handful are visible. Once located, each has an interesting story to tell. The Great Globular Cluster in Hercules (M13) is a frequent target of stargazers with big scopes. It was the target for the only deliberate interstelAmateur Astronomers Association 1010 Park Avenue New York, NY 10028

lar radio message, sent by Frank Drake and Carl Sagan from the Areceibo Radio Dish in Puerto Rico in 1974. It was just a chain of binary code, and, at a distance of some 26,000 light-years, no one's really expecting a reply anytime soon, or ever. Still, it stirs the imagination. Other wonderful deep-sky sights include the Orion Nebula (although I wish it was visible on summer evenings!) and my favorite, M31, the Andromeda Galaxy. It's only a grey smudge in an urban stargazer's telescope, but what a magnificent smudge it is. I always love telling people that the only people on Earth when the visible light set out on its 2.3 million light-year journey were Australopithecines on the savannas of Eastern Africa. Another benefit to city stargazing: There's never a shortage of people who are amazed they can see anything. Perhaps they crave the subtlety, maybe even the reality, in the midst of so much glitz and neon. My favorite sidewalk astronomy moment was during the 2003 blackout. I decided to share the Moon and Mars with city dwellers. Passersby were thrilled to get a glimpse of Mars and the Moon. It was an unexpected touch of wonder in a surreal night, for me as well as those who set out to experience a dark city and encountered Martian landscapes along the way.

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