SHOP NOW FOR SCIENCE & ASTRONOMY PRODUCTS Huge selection! Books • Magazines • Globes & Maps Posters • Downloads • And more! MyScienceShop.com P29014 Background: IC1396 (Elephant Trunk Nebula) Imager: Jerry Gardner Scope: Sky-Watcher Esprit 80 EDT f/5 Sky-Watcher Esprits are on sale throughout October! Designed with the discerning astrophotographer in mind, Sky-Watcher USA’s top-of- the-line refractor delivers the kind of imaging performance one would expect from telescopes costing thousands of dollars more. Sky-Watcher USA Esprits come with everything you see here. False color is a thing of the past with the Esprit’s apochromatic three-element, air-spaced objective lens design. re you I’d take advantage of it. Unlike other refractors, Sky-Watcher USA Esprits ithout notice. 20-18018 include a 2-element field corrector, guaranteeing a flat field across the entire imaging plane right out of the box. The Sky-Watcher proprietary rack- and-pinion focusing system provides a smooth, rock-solid focuser with zero image shift. Esprit refractors are available in 80, 100, 120, and 150mm apertures and come with a 9x50 right-angle finderscope, 2-inch star diagonal, 2-element field flattener, camera adapter, mounting rings, dovetail plate and foam-lined hard case. Act now! You must purchase between October 1st and ©2018 Sky-Watcher USA. Specifications and pricing subject to change w This is only the second time the Esprit line has had sale pricing in America. If I we October 31st, 2018 to be eligible for this offer. For a complete list of specifications and features, please go to skywatcherusa.com 80mm ....... Normally $1,649 .......Sale Price $1,499 .....SAVE $150 100mm ...... Normally $2,499 ......Sale Price $2,299 .....SAVE $200 120mm....... Normally $3,199 .......Sale Price $2,899 .... SAVE $300 150mm ...... Normally $6,399 ......Sale Price $5,999 .... SAVE $400 For information on all of our products and services, or to find an authorized Sky-Watcher dealer near you, just visit www.skywatcherusa.com. Don’t forget to follow us on Facebook, Twitter and Instagram! % Now only $49.90 free shipping! % YOUR TRIP THROUGH THE UNIVERSE! 2017 Universe2go combines the view of the real night sky with the digital world. Look to the sky and discover constellations, planets, and galaxies. WHAT IS UNIVERSE2GO? Universe2go is an augmented-reality star viewer and smartphone app, which shows you the starry night sky in stunning detail! Place your smartphone in the viewer and observe the night sky with numerous, additional bits of information as well as sensational close-ups of various celestial bodies. Images of all 88 Close-ups of planets, More than three hours of Narratives of Greek Enjoyable exploration in constellations of the galaxies, star clusters and audio explanations mythology quiz mode heavens nebulae THE PRESS SAYS ERISEA-MAG.COM: SCIENTIFIC AMERICAN: ASTRONOMY NOW: “A unique and quite frankly “Doing augmented reality “For those at all levels of brilliant thing to have to this way is great, doing experience in astronomy, it hand for anyone who has a personal planetarium- is definitely the next leap in a keen interest in space, come-star-map this way is the evolution of interactive especially children as it is so inspired.” sky map devices.” easy to use.” Incl. Universe2go app unlock code. Now only $9.90 reduced from $99. www.universe2go.com Free shipping! Find more Omegon products at www.omegon.com! Online Content Code: ASY1811 Enter this code at: www.astronomy.com/code NOVEMBER 2018 to gain access to web-exclusive content VOL. 46, NO. 11 NASA/JHUAPL/CIW ON THE COVER Mercury, the closest planet to the Sun, remains a world of mysteries. The BepiColombo spacecraft aims to unravel some of these. COLUMNS 30 Strange Universe 12 CONTENTS BOB BERMAN Observing Basics 62 FEATURES GLENN CHAPLE 20 COVER STORY 36 54 For Your Consideration 64 Voyage to a world Sky This Month Our eighth annual JEFF HESTER of extremes Mars remains a beacon. Star Products Secret Sky 66 A world of both ire and ice, MARTIN RATCLIFFE AND We’ve combed manufacturers’ STEPHEN JAMES O’MEARA Mercury excites and confounds ALISTER LING catalogs and surfed the web to scientists. he BepiColombo come up with a selection of 35 probe aims to make sense of this 38 products that are sure to fuel QUANTUM GRAVITY mysterious world. BEN EVANS StarDome and your astronomical passion. Snapshot 9 Path of the Planets PHIL HARRINGTON Astro News 10 30 RICHARD TALCOTT; Damien Peach images ILLUSTRATIONS BY ROEN KELLY IN EVERY ISSUE the cosmos Although best known for 44 From the Editor 6 planetary photography, the November’s 50 finest Astro Letters 8 author is equally adept at deep-sky objects Advertiser Index 67 capturing comets, stars, and Set aside some time under galaxies. TEXT AND IMAGES BY New Products 68 a moonless sky to view this DAMIAN PEACH wide variety of celestial treats. Reader Gallery 70 MICHAEL E. BAKICH Breakthrough 74 Astronomy (ISSN 0091-6358, USPS 531-350) ONLINE is published monthly by Kalmbach Media Co., 21027 Crossroads Circle, P. O. Box 1612, Waukesha, WI 53187–1612. Periodicals postage FAVORITES 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 News Picture Trips Canada Publication Mail Agreement #40010760. for info on the biggest news and Shop The latest of the Day and Tours observing events, stunning photos, Perfect gifts for updates from Gorgeous Travel the world your favorite the science and photos from with the staff of informative videos, and more. science geeks. the hobby. our readers. Astronomy. 4 ASTRONOMY • NOVEMBER 2018 A Family of Great Products, From a Family Business, 'HGLFDWHGWR For Your Family &UDIWVPDQVKLS to Enjoy! $XWR$GMXVWLQJ *72 0RWRU*HDUER[HV $EVROXWH(QFRGHU 2SWLRQ 9'& With over forty years of design- ing and building our vision for eyepiece and refractor perfor- mance, along with photo/visual accessories to match, Tele Vue &RQQHFWLYLW\ continues its mission to make your observing ”...even better than *72&3 you imagined.” Call for expert and accurate technical advice. ZZZDVWURSK\VLFVFRP 0DFKHVQH\3DUN,/86$ 32 Elkay Drive, Chester, New York 10918 845.469.4551 www.TeleVue.com 3K WWW.ASTRONOMY.COM 5 FROM THE EDITOR BY DAVID J. EICHER Editor David J. Eicher Art Director LuAnn Williams Belter EDITORIAL Senior Editors Michael E. Bakich, Richard Talcott Production Editor Elisa R. Neckar Associate Editors Alison Klesman, Jake Parks Copy Editor Dave Lee Take Editorial Assistant Amber Jorgenson ART Graphic Designer Kelly Katlaps Illustrator Roen Kelly Production Specialist Jodi Jeranek a trip CONTRIBUTING EDITORS Bob Berman, Adam Block, Glenn F. Chaple, Jr., Martin George, Tony Hallas, Phil Harrington, Korey Haynes, Jeff Hester, Liz Kruesi, Ray Jayawardhana, Alister Ling, Steve Nadis, Stephen James O’Meara, Tom Polakis, Martin Ratcliffe, Mike D. with us Reynolds, Sheldon Reynolds, Erika Rix, Raymond Shubinski SCIENCE GROUP Executive Editor Becky Lang alk to any astronomer mesmerizing sights. It’s an As part of the 2019 solar eclipse Design Director Dan Bishop about the job, and important trip to observe tour to Chile and Peru, Astronomy’s EDITORIAL ADVISORY BOARD travelers will visit the famous and Buzz Aldrin, Marcia Bartusiak, Timothy Ferris, Alex Filippenko, they’ll invariably dozens of deep-sky objects ethereal site Machu Picchu, an icon Adam Frank, John S. Gallagher lll, Daniel W. E. Green, William K. Hartmann, Paul Hodge, Edward Kolb, Stephen P. Maran, of Inca civilization. VITMARK/DREAMSTIME tell you that travel is we can’t see at all from the Brian May, S. Alan Stern, James Trefil an exciting part of Northern Hemisphere. Tit. Observatories get built The trip takes place at a Sedona’s red rock forma- Kalmbach Media on mountaintops in exotic base camp near the Gulf of tions, the Grand Canyon, Chief Executive Officer Dan Hickey Senior Vice President, Finance Christine Metcalf locations for a reason — the Nicoya, on Costa Rica’s Lowell Observatory, and Vice President, Content Stephen C. George Vice President, Consumer Marketing Nicole McGuire great seeing and transpar- Pacific coast. There, we can Meteor Crater. Vice President, Operations Brian J. Schmidt ency — so visiting astro- explore the magical forest Check out the details Vice President, Human Resources Sarah A. Horner nomical sites takes you to during the day, as well as at www.astronomy.com/ Senior Director, Advertising Sales and Events David T. Sherman Advertising Sales Director Scott Redmond some pretty cool places in ride horses, watch huge magazine/trips-tours/ Circulation Director Liz Runyon Art and Production Manager Michael Soliday the world. numbers of bird species and 2019arizona New Business Manager Cathy Daniels We take pride in partner- other wildlife, and enjoy And of course, there’s Retention Manager Kathy Steele Single Copy Specialist Kim Redmond ing with TravelQuest soothing waters. At night, as a major trip next year for ADVERTISING DEPARTMENT International, an experi- the stars come out in a dark eclipse chasers. The total Phone (888) 558-1544 Advertising Sales Manager Steve Meni enced touring company sky and the telescopes roll solar eclipse on July 2, 2019, Advertising Sales Representative based in Arizona that will be visible from Dina Johnston, [email protected] Ad Services Representative handles our trip logis- Chile, and we’re run- Christa Burbank, [email protected] tics. On our tours, For more, visit ning a trip that will RETAIL TRADE ORDERS AND INQUIRIES Selling Astronomy magazine or products in your store: editors travel with you www.astronomy.com/ explore that beautiful Phone (800) 558-1544 to provide guidance country as well as Outside U.S. and Canada (262) 796-8776, ext. 818 magazine/trips-tours Fax (262) 798-6592 and astronomical sites in Peru.