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Celestron's Astronomy The Sky-Watcher USA Star Adventurer multi-purpose mount is perfect for anyone — Milky Way photographers, eclipse chasers and budding astrophotographers. It’s the ideal night-and-day, grab-and-go package. Star Adventurer Compact and portable — weighing only 2.5 pounds — this versatile Photo package mount is also powerful. Its quality construction, utilizing precision all-metal Only $319 gearing, delivers an impressive 11-pound payload capacity. The Star Adventurer converts easily from a tracking photo mount to a grab- and-go EQ astronomical mount. Allowing you to spend more time doing what you love and less time setting up. The Star Adventurer features: • Multiple preprogrammed speeds perfect for time-lapse photography, wide angle astrophotography and astronomical tracking • Tracking selectable between multiple rates, sidereal, solar and lunar • Built-in polar scope with illuminator • DSLR interface for automatic shutter control • Built-in auto-guiding interface • Long battery life — up to 72 hours • External Mini USB power support • Compatible with 1/4-20 and 3/8 inch camera tripod • Comes in two packages: Astro pack (includes Dec L bracket) Photo pack (includes ball head adapter) Optional accessories Ball head adapter - $15 Dec L bracket - $40 ©2018 Sky-Watcher USA. Specifications and pricing subject to change without notice. 20-17021. You may have noticed that we’re using a new green on our products. It’s our new look and you’ll be seeing more of it over the next few months. Let us know what you think of it! Latitude base - $65 Counterweight kit - $30 Photographer: Carlos Guana Camera: Canon 5D IV Lens: Rokinon 14mm 2.8 Mount: Star Adventurer For information on all of our products and services, or to find an authorized Sky-Watcher USA dealer near you, just visit www.skywatcherusa.com. Don’t forget to follow us on Facebook, Twitter and Instagram! TIME ED O T FF I E IM R L 70% off O 7 R IL D R ER BY AP Pull Back the Curtain on the Unseen Universe For a few hundred thousand years, we used our eyes as our primary astronomical tool. But all that changed in the 1930s when a young engineer named Karl Jansky detected radiation below the visible part of the spectrum emanating from an astronomical object—and radio astronomy was born. Radio Astronomy: Observing the Invisible Universe takes you on a thrilling journey through astounding discoveries and a virtual tour of the world’s most powerful radio telescopes with Felix J. Lockman, Ph.D., of the Green Bank Observatory as your guide. But perhaps the most astounding of all radio astronomy discoveries is this: The dominant molecular structures in interstellar space are based on carbon. That is not what scientists had expected. We have always labeled these molecules “organic” because life on Earth is carbon based. Now we know the chemistry of the entire Milky Way is organic, not just our home planet, and it is likely that any extraterrestrial galactic life would be related to us, at least on the molecular level. Will we find other organic life forms out there? Radio astronomers don’t know. But they’re certainly working on it. Off er expires 04/07/18 THEGREATCOURSES.COM/9ASTR 1-800-832-2412 Online Content Code: ASY1803 Enter this code at: www.astronomy.com/code MARCH 2018 to gain access to web-exclusive content VOL. 46, NO. 3 NASA/JPL-CALTECH ON THE COVER The Cassini-Huygens mission produced an amazing new understanding of Saturn and its moons. CONTENTS 20 COLUMNS Strange Universe 8 FEATURES BOB BERMAN 20 COVER STORY 38 55 Secret Sky 16 Cassini unveils Saturn StarDome and In pursuit of exoplanets STEPHEN JAMES O’MEARA This intrepid spacecraft spent 13 Path of the Planets Two massive telescopes in the For Your Consideration 18 Lone Star State monitor 450 suns years studying the ringed planet, RICHARD TALCOTT; JEFF HESTER transforming our view of this ILLUSTRATIONS BY ROEN KELLY in the hopes of finding other captivating world. LIZ KRUESI worlds. ROBERT REEVES Binocular Universe 67 44 PHIL HARRINGTON 28 Ask Astro 60 Observing Basics 68 Saturn’s small wonders Brown dwarf jets. The photographic GLENN CHAPLE Usually known for its rings, the legacy of Lowell’s Saturn system is also home to 46 Great Refractor QUANTUM GRAVITY some of our solar system’s most A detailed look Over decades, the observatory’s Snapshot 7 intriguing moons. inside Cassini powerhouse instrument charted a FRANCIS REDDY The spacecraft’s 12 instruments new course in planetary imaging. Astro News 10 showed Saturn and its family KLAUS BRASCH 36 in unprecedented detail. IN EVERY ISSUE Sky This Month RICHARD TALCOTT 64 From the Editor 6 Mercury at its evening best. Astronomy tests Astro Letters 9 MARTIN RATCLIFFE AND 48 Celestron’s CGX mount ALISTER LING 72 minutes on Titan If you’re ready for the next level New Products 66 In 2005, the Huygens probe of telescope mounts, this may be Advertiser Index 69 pierced the moon’s shroud to the one for you. TOM TRUSOCK reveal a surprisingly Earth-like Reader Gallery 70 world. KOREY HAYNES Breakthrough 74 Astronomy (ISSN 0091-6358, USPS 531-350) is ONLINE published monthly by Kalmbach Publishing Co., 21027 Crossroads Circle, P. O. Box 1612, Waukesha, WI 53187–1612. Periodicals post- FAVORITES age paid at Waukesha, WI, and additional offices. POSTMASTER: Send address changes to Astronomy, P.O. Box 62320, Tampa, Fla. 33662-2320. Go to www.Astronomy.com My Science Ask Astro Trips and Sky This Canada Publication Mail Agreement #40010760. for info on the biggest news and Shop Archive Tours Week observing events, stunning photos, Perfect gifts for Answers to all Travel the world A daily digest of your favorite your cosmic with the staff of celestial events. informative videos, and more. science geeks. questions. 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