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September 2006 Webfooted Astronomer The Seattle Astronomical Society September 2006 Special points of interest: • Light Pollution • Hubble Captures A Rare Eclipse On • Strange Space Pinwheels Spotted Uranus September Meeting: Meeting Information Wednesday, September 20 The Southern Sky from New Zealand 7:30 p.m. Denis Jansky Physics-Astronomy Building Room A102 SAS University of Washington Denis will give a Seattle presentation about his Come early at 7 p.m. for coffee recent trip to New Zealand and snacks and to visit with where he had six nights of your fellow members! observing with a telescope he brought for the occasion. Denis will discuss the equipment he brought and where he observed. He also will describe an interesting place where there is a full-scale functioning replica of Stonehenge. He will also share his impressions of the southern sky. If you have questions or suggestions for future In this issue: meetings, don't hesitate to contact me, Bruce Kelley - From the President’s Desk 3 Seattle Astronomical Society - Programs August Meeting Minutes 5 [email protected] September/October Calendars 8 NASA Space Place: 10 Deadly Planets Space Bits: Current News 12 Seattle Astronomical Society Address Web Page: PO Box 31746 http://seattleastro.org Seattle, WA 98103-1746 WebfootWeb: [email protected] SAS Info Line: 206-523-ASTR E-mail: [email protected] Board & Committees Special Interest Groups President: Thomas Vaughan, Dark Sky Northwest: Bruce Weertman, 206-772-1282, [email protected] [email protected] Telescope Makers: Peter Hirtle, Board Chairperson: Stephen Van Rompaey, 206-363-0897, 425-564-8619, [email protected] [email protected] Astrophotography: Keith Allred, First VP–Programs: Bruce Kelley, 425-821-5820, 425-869-8347, [email protected] [email protected] Vive La Lune (Moon): Pat Lewis, Second VP–Education: Burley Packwood, 206-524-2006, [email protected] [email protected] Third VP–Membership: Janice Edwards, Sidewalk Astronomers: Paul Ham, [email protected] 206-522-7410, [email protected] Fourth VP–Publicity: Greg Scheiderer, 206-938-5362, Webfooted Astronomer [email protected] Editor: Vanessa Long Treasurer: Scott Cameron, [email protected] 425-745-5057, Circulation Managers: Pat Lewis & Joanne Green, [email protected] 206-524-2006, Secretary: Chris Karcher, [email protected] 206-789-7945 [email protected] Astronomical League: Bob Suryan, 206-789-0599, [email protected] Webmaster: Paul Rodman, 425-889-8273, [email protected] Club Telescopes & Equipment: Thomas Vaughan, 206-772-1282, [email protected] 222‧Seattle Astronomical Society From the President’s Desk… Light Pollution By Thomas Vaughan Light Pollution As I mentioned during the August meeting, our Dark Sky effort was prominently mentioned in the front-page story of the August 13th (Sunday) Everett Herald! If you didn't get a chance to read the article, you can find it here: http://www.heraldnet.com/ stories/06/08/13/100loc_a1starlight001.cfm The article also points out the general problem of light pollution in Washington State. I'm sure all of us are painfully aware of how hard it is to find dark skies in the greater Seattle area. But I wasn't prepared for how fast dark skies are disappearing from the rest of the state. A few weekends ago, a few of us camped out at a prospective dark sky site in Eastern Washington, between Ephrata and Moses Lake. You can see the report here: http:// www.wavepacket.net/tomva/dark-sky.html As we set up our telescopes during the twilight hours, the site looked very promising! We had a clear 360 degree horizon, and only a few clouds were in the sky. But by midnight it was obvious that the site had too much light pollution for serious observing. Most of the western and south-eastern skies were completely washed out with lights from Ephrata and Moses Lake, respectively. Even looking north, where the skyglow was minimal, we couldn't do better than perhaps 5th magnitude stars. We chalked that up to bad luck, and will continue our search for a dark site east of the mountains. Over the Labor Day Weekend, I visited friends at their cabin along Hood Canal. I brought along my telescope, hoping for clear skies. I was fortunate: Saturday night was very clear, I didn't see a single cloud in the sky. I set up my telescope along the shore, and waited for the skies to get dark. However, the skies were even more light polluted than the prospective site in Eastern Washington. I couldn't see better than 4th magnitude stars. There was a fair amount of Seattle Astronomical Society ‧333 light pollution from nearby houses and towns, but most of the glow (I'm sure) was from the Puget Sound metropolis of Seattle and Tacoma. Even with the light pollution, I had a great hour or so of observing. Andromeda, the Ring Nebula, and M13 remain visible and spectacular. And I'm sure we'll be able to find a dark site for the club. But we also need to do our part to stop--and reverse!--the light pollution that is spreading across our state. The best resource I know of is the International Dark Sky Association, at http:// www.darksky.org. They have a great list of approved light fixtures for practically any use. Do you have outdoor lights, or know someone who does? Visit the site and see if you can recommend a more sky-friendly fixture! I myself am ordering a bunch of simple shields for my outside lights. Sure, it's just a drop in the pond as far as Seattle's light pollution goes, but it's a start. Happy Observing- -Thomas Pictures from SAS Dark Sky Site... 444‧Seattle Astronomical Society SAS August 2006 Club Meeting Minutes Announcements: The date for the annual SAS banquet was announced as 1/13/07. A banquet chairperson is still needed. Rattlesnake Lake access is no longer available due to security changes for the watershed. The turnaround is still available for observing however. The Goldendale star party will be held 9/22 - 9/24 at Brooks Memorial State Park. Contact Karl Schroeder for information. The SAS Dark Sky Site now has 32 members. An active search for property is underway and a weekend trip to a promising site near Ephrata is planned for a coming weekend. The debate continues over the status of current and new planets. Zach Drew provided a well done and lively “What’s Up” presentation which included information on the Ring Nebula, M13, M92, the binary pair with Alberio and epsilon Lyra. Meeting Topic: This month’s topic was show and tell from club members. Maxine Nagel gave a report and showed pictures of the Table Mountain Star Party, Dave Irizarry showed the products of his efforts with his D50 camera, a expertly designed and constructed “barn door” camera mount was shown, Burley Packwood and Jim Peterson showed and talked about their homebuilt Dobsonians, Bruce Kelley demonstrated his new laser finder setup, Thomas Vaughan provided a fascinating galaxy simulation program. Meeting was adjourned around 9:00PM. Seattle Astronomical Society ‧555 Strange Space Pinwheels Spotted [By Robin Lloyd] The heart of one of the Milky Way galaxy's most massive star clusters harbors as many as five pin- wheels, a strange and relatively newly discovered type of stellar object, astronomers say. Initially, scientists using the Hubble Space Telescope took a close look at the Quintu- plet Cluster, naming it after the five red massive and enigmatic stars found at its cen- ter. It was unclear if the stars, called "cocoon stars" for the dust surrounding them, were young or old. Now, the Keck Observatory's 10-meter Keck I telescope on Mauna Kea in Hawaii, the world's biggest telescope, has shown that all five of the stars are approaching the ends of their lives and that at least two of the stars look like pinwheels, rotating around one another. The other stars also might be pinwheels, the scientists say, spewing out dust in a spiral arc in the same way a rotating lawn sprinkler creates a spiral of water. "With five times greater resolution on the Keck Telescope, we could really focus in on the core of the star and drill deep down into the physics of these massive stars, finally answering the mystery of what these enigmatic cocoon stars are," said astrophysicist Peter Tuthill of the University of Sydney, Australia. Tuthill led the group that pub- lished the pinwheel images in the journal Science . Pinwheels, or spirals, are quite rare and exotic in our galaxy, he said. "To find a whole little garden of them in this remote cluster was startling and beautiful," Tuthill told SPACE.com . The dust plumes around the two pinwheel stars are typical of objects called colliding- wind binaries, he said. These stars, between 10 and 20 times the mass of our Sun and 10,000 to 100,000 times brighter than it, are exotic rarities found only among old mas- sive binaries. The pinwheel discovery suggests that many of the very luminous stars in our galaxy, most of which are surrounded by dust, are actually massive binaries, not single stars, Tuthill said. 666‧Seattle Astronomical Society The five brightest Quintuplet stars lived fast and are dying young. They have burned off all their hydrogen and now are fueled by helium and fuse it into heavier elements, he said. In a binary system, such stars generate strong stellar winds that collide to cre- ate a lot of dust. The dust at the collision front between the stellar winds is carried around as the stars orbit, trailing dust that turns to create the pinwheel effect.
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