1、For information on all of our products and services,or to find an authorized Sky-Watcher USA dealer near you,just visit .Dont forget to follow us on Facebook and Twitter!Regardless of whether you prefer visual astronomy or astrophotography,Sky-Watcher USA has something for everybody including some s
2、pectacular savings.For the month of April our entire Maksutov and Quattro lines are on sale.From the ultra-portable 90mm Mak-Cassegrain,all the way up to our impressive 12 Quattro imaging Newtonian,you can get crisp views and flat fields for less.From April 1,2018 through April 30,2018,all of our Ma
3、ksutovs and Quattro imaging Newtonians will be on sale.Dont miss out on some of the best savings of the year!2018 Sky-Watcher USA.Specifications subject to change without notice.20-18005.If youre in New York on April 21-22,come visit us at the Northeast Astronomy Forum!Save up to$150 on Sky-Watcher
4、Maksutovs and Quattro imaging Newtonians during April!Regular price Sale price You save 90mm Mak-Cassegrain.$220.$190.$30102mm Mak-Cassegrain.$265.$230.$35127mm Mak-Cassegrain.$435.$400.$35150mm Mak-Cassegrain.$750.$680.$70180mm Mak-Cassegrain.$1200.$1075.$125190mm Mak-Newtonian.$1550.$1400.$1508 Qu
5、attro.$640.$600.$4010 Quattro.$815.$760.$5512 Quattrop.$1279.$1189.$9032 Elkay Dr.,Chester,New York 10918 (845)469-Tele VueVi s i o n a r ytelevueopticsIt took Dr.Don Bruns two-and-a-half minutes to create history with a Tele Vue-NP101is.During totality of the 2017 total solar eclipse,he imaged the
6、star field around the Sun in an attempt to make the most accurate optical measurement to date of Einsteins prediction of starlight deflection.His goal was to use off-the-shelf equipment available to any amateur astronomer.Hear Don present his history-making results,and why he chose a Tele Vue telesc
7、ope,at NEAF 2018;then stop by the Tele Vue booth to see the scope,speak with Don,and choose a Tele Vue telescope of your own!Whether you make family or scientific history with it,Tele Vues line of APO refractors are heirloom-quality instruments,built in New York,to stand the test of time and challen
8、ges of space!Follow our blog at T for Dons and other Tele Vue owners stories.Some Tele Vue Telescopes have only a day to make history,others have a lifetime!Make Some History with a Tele Vue Telescope of Your Own!Image courtesy of Don BrunsIllustration of the Tele Vue-NP101is image identifying quali
9、fying stars used to measure positional deviation due to the Suns gravity.Booths 524-526CONTENTS4 ASTRONOMY MAY 201822 COVER STORYNew insights into how the solar system formed Recent observations reveal that chaos and mayhem ruled our planetary systems irst days.JESSE EMSPAK28An organically grown pla
10、net definitionShould we really deine a word by voting?KIRBY D.RUNYON AND S.ALAN STERN 30Seeking the unknown in cosmic data In an era of large-scale surveys,citizen science projects,and new machine-learning techniques,unexpected discoveries should be expected.MARA JOHNSON-GROH36Sky This MonthJupiter
11、shines brilliantly.MARTIN RATCLIFFE AND ALISTER LING38StarDome and Path of the PlanetsRICHARD TALCOTT;ILLUSTRATIONS BY ROEN KELLY44Ask AstroBlack hole jets.46Why do galaxies align?he matter in our universe forms ilaments and threads like a grand cosmic web,tugging galaxies and clusters into place al
12、ong the way.MICHAEL WEST 52 Leos exotic deep-sky gemsBeyond the brightest galaxies,the Lion contains many challenging deep-sky targets.STEPHEN JAMES OMEARA58Observe Mars at its bestIts been 15 years since the Red Planet was this close and this big.Set up your scope,and take advantage of this apparit
13、ion.MICHAEL E.BAKICH 62Guide your camera to great shotsA variety of mounts and techniques can help you create stunning images.Which one is for you?MIKE REYNOLDS 66Capture video with this low-cost camera Lots of accessories make the RunCam Night Eagle an easy match for any telescope or camera lens.RI
14、CHARD P.WILDSCOLUMNSStrange Universe 10BOB BERMANSecret Sky 14STEPHEN JAMES OMEARAFor Your Consideration 16JEFF HESTERBinocular Universe 18PHIL HARRINGTONObserving Basics 70GLENN CHAPLEQUANTUM GRAVITYSnapshot 8Astro News 12IN EVERY ISSUEFrom the Editor 6 Astro Letters 11 New Products 68Advertiser In
15、dex 69Reader Gallery 72Breakthrough 74FEATURESMAY 2018VOL.46,NO.530Astronomy(ISSN 0091-6358,USPS 531-350)is published monthly by Kalmbach Publishing Co.,21027 Crossroads Circle,P.O.Box 1612,Waukesha,WI 531871612.Periodicals post-age paid at Waukesha,WI,and additional offices.POSTMASTER:Send address
16、changes to Astronomy,P.O.Box 62320,Tampa,Fla.33662-2320.Canada Publication Mail Agreement#40010760.ONLINE FAVORITES Go to www.A for info on the biggest news and observing events,stunning photos,informative videos,and more.RON MILLER FOR ASTRONOMYON THE COVER For years,planetary scientists thought our solar system formed in a simple way.Now the picture is more complex.Trips and Tours Travel the world with the staff of Astronomy.Sky This Week A daily digest of celestial events.Picture of the DayGo
