Sky & Telescope July 2010

Lessons from Twins of the Sun p. 22 THE ESSENTIAL MAGAZINE OF ASTRONOMY Pluto Crosses “Hole in the Sky” p. 60 JULY 2010 Hidden in Plain Sight How an amateur astronomer discovered the Soap Bubble Nebula p.34 Use the Whole Sky: Shooting Near the Horizon p. 72 Walt Whitman’s “Strange Huge Meteor Procession” p. 28 S&T Test Report Update of a Classic p. 54 Visit SkyandTelescope.com TeleVue.com ® 200+ Products for a Universe of Needs ( and we just added the longest Ethos focal length, 21mm! ) In this multifaceted hobby, the one interest amateur astronomers share is the desire to own well engineered products that work as intended, and deliver performance that stands the test of time. After all, isn’t that ultimately the true value of your purchase? It has been nearly thirty years since Tele Vue Plössls hit observing fields and we’re proud their performance is still rated “tops in the field.” Thirty years from now we expect our new Ethos eyepieces will still be as highly regarded as today. The same holds true for our current, highly acclaimed APO refractors, whose forbearers pioneered the concept of multipurpose, high performance, portable telescopes. Explore www.TeleVue.com. Discover a Universe of products engineered, manufactured and inspected to be “even better than you imagined.” APO refractors 60-127mm Paracorr Coma Corrector Naglers—82° AFoV Powermate Tony Hallas:NP101is New 21mm Ethos—100° AFoV Joins the 6, 8,10, 13 & 17mm Family! Dioptrx Starbeam Focusmate—6:1 reduction Nagler Zooms Tim Puckett:NP127is “Positively revolutionary...If you like wide-field eyepieces, you really have GOT to own the Ethos - ATT Nov/Dec 2009 Tim Puckett:NP127is Filters Dielectric Diagonals Plössl—50° AFoV Jim Burnell:NP127is Sol Searcher Camera Adapters Panoptic—68° AFoV Air-Chair Barlows Tele Vue Logo Wear Tele Vue Vi s i o n a r y Bino Vue CCD Imaging System Radian—60° AFoV ® 32 Elkay Drive, Chester ork 10918 Chester,, New Y York worldmags & avaxhome 845.469.4551 www Vue.com www.. Tele eleV worldmags & avaxhome July 2010 T. RECTOR / H. SCHWEIKER / NOAO / AURA / NSF VOL. 120, NO. 1 On the cover: A Kitt Peak professional scope imaged the Soap Bubble here, but it was discovered by an amateur astronomer. FE ATURE S THI S M O N TH ’ S S K Y 40 Solar Twins 6 By Fred Schaaf 43 July’s Sky at a Glance 45 Binocular Highlight 48 8 10 28 Walt Whitman’s “Year of Meteors” A team of astro-sleuths from Texas State University once again sets the record straight — this time for one of America’s most famous poets. By Donald W. Olson, Marilynn S. Olson, Russell L. Doescher, & Ava G. Pope 51 Letters 50 & 25 Years Ago By Leif J. Robinson Planetary Almanac 14 News Notes Sun, Moon, and Planets 20 Cosmic Relief By Fred Schaaf The Sun’s closest stellar analogs hold clues to our own star’s past and future. By Jeff rey Hall Spectrum By Robert Naeye By Gary Seronik 46 22 Lessons from Northern Hemisphere’s Sky AL S O IN THI S I S S U E Exploring the Moon By David Grinspoon 58 New Product Showcase 70 Telescope Workshop By Charles A. Wood 60 Celestial Calendar By Gary Seronik By Alan MacRobert 63 76 Gallery 86 Focal Point Going Deep By Ken Hewitt-White By An