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Journal of the Amateur Astronomers Association of New York June 2008 Volume 56 Number 6, ISSN 0146-7662

EYEPIECE
Global snow cover, an important surface feature for reflecting the Sun's radiation, has declined by 12 million square kilometers during the past half century.

Climate Change: We Know Less than You May Think
By John Delaney
Few modern issues h a ve b een a s vigor ou sly exa m ined by scientists as climate change and, in particular, the role of human activities in altering the composition of the atmosphere. But distortions and misunderstandings on climate change still persist, according to Columbia University astronomy-department chair Dr. David Helfand in his AAA lecture, "Climate Change: What We Do and Do Not Know," at the AMNH May 2.
It should be easy enough, he reasoned. To a physicist, global temperature and climate are a simple concept: energy in, energy out. On the energy-in side, Helfand listed astronomical variables that play a role in global warming. The Sun's output and 11-year sunspot cycle, climatic precession and the tilt of the Earth all vary over time and change the amount of energy reaching the Earth. The changing shape of the Earth's elliptical orbit over 110,000 years has profound effects on temperature and level of carbon dioxide in the atmosphere. Another important factor in t h e en er gy eq u a t ion is the Earth's reflectivity, as determined by cloud cover, ice, vegetation and aerosols. Currently, 31% of sunlight is reflected into space, but this percentage changes over time. "Clearly over the last 20,000 years [the ice cover] has shrunk a lot because there used to be a glacier one mile thick over where you're sitting in your seat." On the energy-out side, Helfand showed how greenhouse gases--water vapor, carbon dioxide, methane, nitrous oxides and chlorofluorocarbons--have increased markedly in the past 200 years. Carbon dioxide has risen from 316 parts per million in the 1950s to 380 now. Since 1950, global temperatures have risen by 1.3 degrees and global sea level has increased by 2.9 inches.

Even with current in st r u m en t a l d a t a , t h e in it ia l lack of long-term data presented climatologists with a major challenge in determining if humans contribute to climate change. Tree rings have been pivotal in extending data sets on temperature, precipitation and other info, going back 12,000 years for every ring. Ice cores, complete with frozen samples of atmosphere and its contents, go back 500,000 years. Ocean-floor sediments, fossils and rocks extend available data to the planet's origins. With this long-term view of climate, researchers can start to convincingly answer the question of how significantly humans are influencing the Earth's climate. The real obstacle t o a ch ievin g a ccu r a t e p r ed ictions is the phenomenon of feedback, including positive Climate Change continued on page 12

Tyson, Memorializing Hess, Makes Offer We Hope You Won't Refuse
Speaking at last month's AAA a n n u a l m eet in g, Hayden Planetarium director Neil deGrasse Tyson, who was mentored by the late Fred Hess, offered to give the club up to $3,000 if donations are matched by members. Money would be in memory of Hess, the former AAA president and longtime voice of Hayden sky shows, who died last year. "Fred inspired me to enter the career I did," Tyson noted. He stipulated funds be used for new programs or equipment at the club, not to pay bills.


What's Up
By Tony Hoffman The Sky for June 2008
A BoÆtid Meteor Surge? T h e J u n e BoÆt id s a r e a rather obscure meteor shower that occurs each year between about June 22 and July 3. These meteors, fragments of Comet 7P/Pons-Winnecke, radiate from northern BoÆtes, above the kite-shaped figure that marks the Herdsman's torso and head. Though the shower is usually feeble, brief outbursts were observed in 1998 (~100 meteors per hour) and 2004 (~50 per hour). Earth is scheduled to encounter the comet's debris trail late on June 26, so the night of June 26-27 is when any outburst would likely occur. The radiant will be perfectly placed for observing, high in the sky and visible all night. A Plenitude of Planets. M a r s a n d Sa t u r n b ot h lie in Leo this month. Saturn is to the east of Regulus, while Mars prowls western Leo, closing to within a degree of Regulus by month's end. At magnitude 0.8, Saturn is the brightest of the three, while Mars at magnitude 1.6 is just fainter than the "Kingly Star" (mag. 1.4). On June 6, a crescent Moon lies to Mars's lower right, while the next night the Moon stands below Saturn and Regulus. Saturn's rings have been slowly closing to our line of sight; next year they'll be edge-on to us and even become invisible for a few weeks. Saturn's largest Moon, Titan, is visible in even the smallest telescope at magnitude 8.6, while a 4- or 5-inch scope will reveal several more. Working inward from Titan, you'll encounter Rhea at magnitude 9.7. Dione and Tethys are still closer to Saturn and fainter than Rhea. Far-ranging Iapetus is one of the most intriguing objects in the solar system, with one side black as tar and the other white as snow. When Iapetus is west of Saturn and its bright side faces us, it can be as bright as magnitude 10 (and visible in a 3 -inch scope), but when east of Saturn with its dark face exposed, it fades to magnitude 12. Even as Saturn sets, Jupiter swings into the scene, rising around 11 p.m. in early June and in evening twilight by the end of the month. Jupiter is east of the Sagittarius "teapot." It's nearly as far south as it ever gets, but its relatively low altitude shouldn't prevent observers from getting some great views of its cloud belts and four large moons. On June 20, Pluto comes to opposition near the
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The Moon joins Saturn, Mars and Regulus in Leo early in the month. star 6 Sagittarii. At magnitude 13.9, you'd probably need an 8-inch telescope to glimpse this iceball, now classified as a dwarf planet. June 3 Moon at perigee, 221,985, 9:21 a.m.; New Moon at 3:23 p.m. June 7 Moon lies near Mars. June 9 Moon lies near Saturn. June 10 First-quarter Moon at 11:04 a.m. June 12 Asteroid 3 Juno at opposition. June 17 Moon lies near Antares. June 18 Full Moon at 1:30 p.m. June 20 Moon lies near Jupiter; summer solstice at 7:59 p.m.; dwarf planet Pluto at opposition. June 26 Last-quarter Moon at 8:10 a.m.; BoÆtid meteor shower peaks. June 30 Moon lies near Regulus; Moon passes through Pleiades, 2-4 a.m.

Jupiter the Chamelion
By Joseph A. Fedrick
Last year the equatorial region of J u p it er wa s changed. The normally pale equatorial region between the two dark equatorial belts had darkened in March and then the South Equatorial Belt faded to near invisibility as seen in instruments of small aperture such as my 60mm refractor. In fact, by June 30 the South Equatorial Belt was hard to locate even in an 8 inch Schmidt- Cassegrain scope. Jupiter maintained its changed appearance into the fall as it sank into the early evening twilight. Fedrick continued on page 11


A Message from AAA President Richard Rosenberg
Hello, members: As I write the day after our annual meeting, I am still pumped up. It was my privilege to award the Amateur Astronomers Medal to two outstanding people, Eddie Oravec and Bob Little. Neil Tyson took time from his busy schedule to come by and offer a $3,000 matching grant for the club in honor of Fred Hess. We heard a wonderful piece by flutist Eileen Ain honoring Fred. In Dan Harrison's article below you'll find more details on our annual meeting. My primary goal this past year has been to find a more suitable headquarters for the club. Although this hasn 't yet been accomplished, we have established a relationship with New York University.

The Recent Advances in Astronomy Seminar met at NYU May 8. Thanks to chair Mary Carlson, the meeting was a great success. Since we now have a laptop and could use the up-to-date facilities at NYU, topics we discussed could be illustrated with photos, charts and diagrams. We watched a NASA movie on the landing of the Phoenix Mars Lander. Previews of May's celestial events were depicted using a planetarium program. I hope you can make it to the next seminar June 12. The room isn't set yet, so check our website or give me a call. I hope we'll soon be able to move our other indoor events to NYU.
Thanks to webmaster Marcelo Cabrera, we added advertising to our website this year. While it 's not currently a big source of revenue, every little bit helps. I hope you'll patronize our advertisers. In the near future we hope to reach another goal, an online version of Ey epiece that can be e-mailed to members. This will save considerable printing and mail costs. Because the online version won 't be limited by space considerations, extra material such as photos can be included. Members can choose to continue receiving the print version. We continue to battle against light pollution, and bills to attack it have been introduced in the City Council. I participated in a press conference at City Hall May 14. See Dan's article on the latest developments on page 4. On May 10 we had a wonderful observing session at Riverside Park. The clouds cleared just in time for us to check out the Moon (with the Beehive Cluster nearby), Mercury, Saturn and Mars. The public turnout was large, with many children. We'll try to schedule another event there this summer. At the board meeting following the annual meeting, directors granted me another year as president. I thank them and you for this opportunity. Rich Rosenberg, AAA President, pr esident @a a a .or g, (718) 522-5014

Eddie Oravec's Look Back at a Wonderful Life in Astronomy
By Dan Harrison
Last month's AAA annual meeting home stretch when Edward (Eddie) Oravec dium. He and Robert Little had just been pr the rarely-awarded Amateur Astronomers club's highest honor. wa s in t h e took the poesented with Medal, the The 83-year-old Oravec, who joined the club's nowdefunct Junior Astronomy Club 70 years ago next year and the AAA 65 years ago, held his audience transfixed as he spoke without a note. It was easily the highlight of a meeting that usually travels along predictable lines. Continued on page 5
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NYC Councilman Introduces Light-Pollution Bills
By Dan Harrison
The battle to enact ligh t -pollution legislation, which has sputtered at the state level for almost a decade, extended to a new front last month when New York City Councilman Alan Gerson introduced the first two of four bills that will comprehensively address the problem. Terming the four bills a means of lighting the city "safely and sanely," Gerson, whose district encompasses most of lower Manhattan, said they were initiated as part of his "quality of life" campaign. "We get many complaints from constituents," he told a May 14 press conference. "This will save eyesight, energy and money." The first bill, unveiled that day, requires fully shielded light fixtures on city streets. "Our street lights shine in all directions. Shields will direct light downward, utilizing light more efficiently and thereby reducing the need for excess power," Gerson said. "This bill will save the city millions of dollars annually and cost nothing, since it requires replacement light fixtures only after they burn out and require replacing. In addition to reducing glare and improving night lighting, we will see the reduction of tons of CO2 and other emissions which are by-products of electricity production. On May 21, Gerson in t r od u ced t h e secon d b ill. This provides a performance design criterion for illuminated signs. The bill will require billboards and other illuminated signs to be lighted efficiently by requiring all light fixtures to shine at least 90% of their total light emissions toward the face/surface of the sign. The two bills are awaiting hearings. None had been scheduled at presstime. Gerson's third bill, awaiting introduction, would require commercial and government buildings to install interior motion detectors so office spaces uninhabited after hours will automatically shut off their lights. The fourth bill is a n a n t i-glare bill, which will require exterior lights which excessively shine into apartments or offices be fitted with shields to block unwanted glare.
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on the prognosis in the transportation committee, but noted that chairman John Liu is one of the sponsors of the bill, "so that is a very good sign." Bills generally get two hearings and unlike Albany, council hearings are public and the public is invited to testify, Nagle said. "We are under the impression t h a t t h e cit y's Department of Transportation (DOT) objects to state legislation for jurisdictional reasons and wouldn't be opposed to a city bill for fully-shielded fixtures," Nagle added. "Jurisdictional objections could be mitigated by removing the city from a state bill, but we haven't discussed that possibility with Albany yet." In the past, city officials have raised cost concerns about the shielding requirement. Speaking at the press conference, AAA p r esid en t Richard Rosenberg said that "In a dark night sky about 2,500 stars should be visible to the naked eye. We see less than 100 from New York City. There's only one reason for this: Light meant to illuminate the Earth is spewed upwards into the sky. This is wasted light. It can be eliminated with appropriate lighting fixtures. "By directing all light to the ground where it's needed, we can generate the same amount of useful light with less wattage. Less wattage means less energy means less old-fashioned pollution and less cost. Some may not agree seeing 2,500 stars is important enough to take action, but in a time of $120 barrels of oil and concern for the environment, we all have something at stake." Meanwhile, the State Assembly h a s p a ssed a b ill which authorizes the State Health Department to "engage in and/or support research into the health impacts of artificial night light." A matching bill has been introduced in the Senate. Bills similar to earlier ones requiring shielded fixtures were reportedly in preparation late last month.

Correction
An item last month on a new New York chapter for the International Dark Sky Association incorrectly gave its website as www.nvida.org. It's www.nyida.org.

Gerson spokesman Paul Nagle declined to speculate


Rosenberg Outlines Club's Achievements and Goals
Continued from page 3 When he finished, the applause was loud and long. Long before Oravec was one of the founders of the AAA's Observers Group, president of the American Association of Variable Star Observers, winner of its observational astronomy award and much more, it was the early 1930s. He viewed a partial solar eclipse and, as he put it simply, "that woke me up to astronomy." ed last year, was elected to a full term and Shana Tribiano, who teaches astronomy at Borough of Manhattan Community College, was elected as a new member. After the meeting, the board re-elected president Rosenberg, vice president Davis, treasurer Haeberle and corresponding secretary Ron McCullough. Alice Barner was elected financial secretary, Fox recording secretary. At the meeting, R osen b er g n ot ed h is goa ls for t h is past year included finding a new location for indoor events like the Recent Events in Astronomy Seminar and Observers' Group. "We have built a relationship with New York University, and the first meeting of our seminar at NYU was May 8. "With a laptop the club purchased, we could get the benefits of a wired environment and provide up-to-the-date news. Beautiful and enlightening images, star charts and movies were presented. Special thanks go to seminar chair Mary Carlson. Webmaster Marcelo Cabrera handled the technical end." Another goal was to add ads to the club's website. "This has been done in the last few weeks by Marcelo, using Google Ads. The ads are not distracting and are appropriate for the club. The club makes some money when a link for an ad is clicked, and more money if a purchase is made at the advertiser's website. Please do not constantly click links to raise money for the club. It's unethical, and Google checks for such activity." Rosenberg outlined goals for t h e u p com in g yea r : 1) Complete the transition of indoor events to NYU and leave 1010 Park Avenue; 2) Give members a choice of receiving Ey epiece online. 3) Add a monthly observing session in a dark-sky environment. 4) Help pass measures to fight light pollution at city and state levels. 5) Prepare a Power Point presentation for the club's class. 6) Get more members involved in helping run the club. Before the meeting, a presentation honored Fred Hess, the former AAA president and longtime voice of Hayden sky shows, who died last year. It was a musical performance of "The Celestial Panorama," part of "Star Peace," a work Hess took part in creating. Composer Dr. Eileen Ain performed on flute, and Rosenberg narrated Hess' words.
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Searching for information on h is n ew in t er est , Oravec had trouble finding good sources until he discovered the AAA. He was greatly influenced by Clyde Fisher, director of the new Hayden Planetarium and the AAA's first president when the club was founded in 1927. The organization had a separate club for younger people, the Junior Astronomy Club. Oravec joined it in 1939 and especially became involved with what would become his passion: observing, which would eventually lead to some 172,000 observations of variable stars.
In 1943, the 19-yea since the junior club was The junior club spawned including a Nobelist in AAA and the junior club r-old Oravec joined the AAA for high schoolers and younger. many professional astronomers, physics. At the time, both the featured two lectures a month.

In 1952, Oravec joined a committee to gauge the feasibility of an observers' group. After the OG was formed, it had 100 members at its peak. Like the AAA's optical group, the OG served as an autonomous entity. Oravec went on countless out-of-city observing expeditions, including many to the north fork of Long Island, other parts of the U. S. and Canada. Accepting his award, L it t le, a lea d in g a st r op h otographer who has written and taught on the subject and who, with Fred Hess, determined that astrophotography from a ship was doable, modestly said that "When I was notified of the award, I said, `What the heck for?'" He said that if he could give medals out, they'd go to board members and other contributors to the club's success. At the meeting, members elected board members Rik Davis, Thomas Haeberle, Bruce Kamiat and Michael O'Gara to new three-year terms. Edward J. Fox, appoint-


New Mercury Images are Fascinating but Bleak
By Terrell Kent Holmes
More than 30 years a ft er it s la st exp lor a t ion , NASA has finally gotten back to exploring Mercury. The MESSENGER (Mercury Surface Space Environment Geochemistry and Ranging) spacecraft launched in 2004. MESSENGER has made several flybys of Mercury and will go into orbit in a few years. Sean Solomon, principal investigator for the mission, recounted the history of the mission, from inception to flybys, at an April 14 Hayden Planetarium lecture. Solomon called Mercury "one of the solar system's oddballs, because it's extreme in a variety of respects." Mercury is the closest planet to the Sun and has the highest range of temperature between day and night: 1,100 degrees F. He also noted that Mercury has a very unusual 3:2 spin ratio with the Sun. Consequently, there's a substantial difference between the day on Mercury as measured by a distant observer and an observer on the surface. "If you stood on the surface and counted the time between successive passages of the Sun, the day would be two Mercury years long," Solomon explained. He also noted that Mercury actually has a tail made of sodium, about 100 planetary radii long, pointing away from the Sun. Solomon painted a fascinating if b lea k p ict u r e of conditions on Mercury's surface. The hypothesis has been advanced that Mercury has ice at its poles. "Mercury [is] almost perpendicular to its orbital plane to within two minutes of arc, nearly zero degrees," Solomon said. "The atmosphere is so thin it doesn't transport heat. As a result, you're staring out into black space at the poles, in permanent shadow, and it's very cold." The temperature there is -180° C., cold enough to store polar ice for billions of years. Therein lies the paradox that the planet with one of the hottest surfaces may also have a substantial quantity of polar ice. The only other spacecraft to visit Mercury was Mariner 10, which flew by three times in 1974 and 1975, with each flyby being one solar day. "Every time Mariner 10 flew by the same side of [it] was in daylight, so there was an entire side...that was never viewed. And that's been it for 33 years."
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The only constraints on MESSENGER, Solomon said, "are cost of the mission, length of development, and launch vehicle you could purchase. And they're judged on the basis of science [and] technical readiness." The two most critical parameters for construction of the spacecraft were that it had to survive being close to the Sun and close to a hot planet. "We solved that problem for most of the spacecraft by a sunshade, [which is] kept between the Sun and the spacecraft at all times." Solomon described the logistics of p u t t in g t h e craft in orbit. "To send a spacecraft towards the Sun it picks up speed, and to go into orbit around Mercury you have to go slowly enough past the planet so that whatever propulsion system you have you can fire it and go into orbit. So we packed as much propellant as we could but were still limited in the change of speed we could impart to the spacecraft. Our launch mass was 55% propellant and 45% dry mass. We didn't have enough propellant to go into orbit the first time we flew by. When we flew by in January we were at about 70 kilometers per second. The next time we fly by in October we'll go a little more than two kilometers per second less. The third time we'll go slower still. At the fourth encounter, when we fire our engines, all we have to do is change the velocity by about a kilometer per second to go into orbit." Solomon showed the first close-ups since Mariner 10. MESSENGER has gotten closer than any Mariner passage. "The great thing about these fly-bys is that we're getting new data...for the first time in 33 years even though we're still three years away from orbit insertion." Moreover, in places that Mariner 10 had imaged, MESSENGER took images under different lighting conditions and with better resolution, so it caught tectonic features Mariner missed. MESSENGER's second view of M er cu r y will a lso be from about 200 kilometers. It will be the second of the three fly-bys. "In another six months we'll fill in almost the rest of the map. So between the 45% that Mariner 10 did, the 21% we added in January, and the 31% we'll image for the first time in October, we'll at 97%. So before we get into orbit we'll have seen most of it."


Review: Joining the Digital Astrophotography Revolution
By Tony Hoffman
When I heard t h a t M ich a el C ovin gt on h a d com e out with a book about astrophotography using digital SLR cameras, I was excited and intrigued. His book "Astrophotography for the Amateur" is one of the classic books on photographing the night sky. It's been through two editions and was last updated in 1999. Even that updated edition was mostly about film photography, with a little bit about CCD astronomy thrown in, and I wondered how he'd adjusted to the digital age. Low-priced Digital SLR cameras (DSLRs), starting with the Canon Digital Rebel and the Nikon D70, have taken the astronomical world by storm in the past half decade, quickly--along with their CCD brethren--all but replacing film cameras among amateur astronomers. In reading "Digital SLR Astrophotography" (Cambridge University Press, $45, paper), I got my answer: very well, thank you. Covington has put together a comprehensive guide to the subject that's a great introduction to DSLR astrophotography for beginners, with lots of very useful material for veterans as well. I have a particular interest in the subject, as almost all of my astrophotography in recent years has been with digital SLR cameras (DSLRs), and found a lot that I've been able to apply. The book is split in t o t h r ee sect ion s: b a sics; ca m eras, lenses, and telescopes; and digital image processing. The basics section includes information on selecting a DSLR, how to adjust its menu settings for photographing the night sky, and gives a few simple projects to start you off, such as shooting the Moon through a tripod-mounted scope. The one thing I felt Covington gave short shrift to is deep-sky photography with an unguided, tripod-mounted DSLR. By taking a series of short exposures (5 seconds or less) through a telephoto lens, then stacking them using software designed for astrophotography such as Registax (I personally use DeepSkyStacker), one can take very effective short exposures of galaxies, nebulae, star clusters, comets and star fields. Otherwise, For instance, t the beginning trick," putting the author touched on most everything. o avoid the effects of a tripod shaking at of a long exposure, you can use the "hat a hat or other dark object in front of the lens, opening the shutter, then moving the hat out of the way once the tripod has had a few tenths of a second to settle down. Covington discusses the importance of using "dark frames" to counteract the effects of the electronic noise "signature" that every digital camera generates. The second part of t h e b ook is a b ou t t h e op t ics of cameras, lenses and telescopes, and different methods of linking camera to telescope. For instance, if you have a telescope with a computerized drive to track the stars, you can "piggyback" the camera on the scope so the camera stays pointed at the same stars as the telescope tracks them. You can also use an adapter to hook the camera (with lens removed) directly to the telescope, so the telescope in effect acts as a huge telephoto lens for the camera. Then there's afocal coupling, pointing the camera (with lens) directly into the telescope's eyepiece, often with a camera mount to keep it rigidly placed. There are several other methods, and Covington goes into the optical principles behind them, and the adapters you can use to link camera to telescope. He goes into detail about the different kinds of lenses one can use. He discusses focusing methods, and how to guide an exposure so the camera/telescope stays pointed where you want it to. He outlines the different methods, manual and computerized, of focusing the camera (you can't just set the lens on infinity). I availed myself of a right-angle finder to provide an easier (and magnified) view of what the camera is pointed at. The last section cover s im a ge p r ocessin g, u sin g MaxDSLR and other software programs to adjust, combine and enhance images. Even simple suggestions such as using Unsharp Mask in a program like Photoshop to sharpen images of the Moon yield immediate results. Stacking and aligning images, removing noise and compensating for lens defects are some topics covered. The book is very detailed, trying to encapsulate a very complicated subject, and is the sort of text I'd jump around in rather than reading straight through, looking for tidbits particularly useful to me. It only served to whet my appetite for trying to take the best astrophotos I can, knowing that when I fall short there will always be
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Briefs: Phoenix Mars Lander to Look for Evidence of Life
NASA's Phoenix Mars Lander sp a cecr a ft su ccessfully landed in the northern polar region of Mars May 25 to begin 90 days of digging in the permafrost to look for evidence of the building blocks of life. The first images transmitted about two hours after landing showed one of its feet sitting on Martian soil amid tiny rocks and a view of the horizon of the arctic plain. Another image showed the lander's solar panels had deployed. Phoenix plunged into the atmosphere at more than 12,000 mph after a 10month, 422 million-mile voyage. Yet oddities remained that didn't match theoretical predictions: The rings protrude beyond the orbit of the moon Thebe, and part of the ring system is tilted compared to the main ring plane. Alternating light and shadow cause these anomalies, new research finds. By listening to the "ringing" of a n ea r b y p la n et harboring star, astronomers have identified the birthplace of one of our galaxy's many drifting stars. Iota Horologii, 56 light-years away near the southern-sky constellation Horologium, has a planet twice Jupiter's size. The star is in the Hyades stream of stars, many of which are thought to be drifting. Astronomers identified Iota Horologii's parentage by studying how sound waves move through a star. The approach could be used to ID other orphaned stars, an estimated 20% of stars within 1,000 light-years of the Sun. The star is 1.5 times as metal-rich as the Sun, which was the clue astronomers needed to figure out it came from the Hyades cluster. Iota Horologii has the same metal abundance and age as the cluster. Ancient hydrothermal springs m a y h a ve b een spotted on Mars. Spri