My first Magazine Sky & Telescope - 04.2019

CONTENTS THE ESSENTIAL GUIDE TO ASTRONOMY April 2019 VOL. 137, NO. 4 FEATURES 14 Spendthrift Spirals The great spiral galaxies that adorn the modern universe are running out of gas and may someday lose their beautiful shapes. By Ken Croswell These far-southern constellations rank near the top in beauty, brightness, and historical interest. By Tony Flanders 54 OBSERVING 41 April’s Sky at a Glance 43 Follow these tips to get the most out of a Messier Marathon run from higher latitudes. By Alan Whitman 34 Alpha Centauri Fever The allure of the closest star system to ours infects astronomers and venture capitalists alike. By Javier Barbuzano 68 Nurture Your Newt II: Collimation Aligning your reﬂ ector’s mirrors — critical to getting the best view — is easier than you think. By Jerry Oltion Find us on Facebook & Twitter Binocular Highlight By Mathew Wedel 2 COLUMNS / DEPARTMENTS 4 Spectrum By Peter Tyson 46 6 From Our Readers Under the Stars By Fred Schaaf 7 75, 50 & 25 Years Ago By Roger W. Sinnott Sun, Moon & Planets By Fred Schaaf 8 News Notes 48 Celestial Calendar By S. N. Johnson-Roehr 52 66 New Product Showcase 72 Astronomer’s Workbench By Jerry Oltion 74 Gallery Exploring the Moon By Charles A. Wood 54 Deep-Sky Wonders By Sue French 76 Book Review By S. N. Johnson-Roehr 57 Going Deep By Mel Bartels 84 Focal Point By Carl Lindemann ONLINE ASTRO TOURISM Come with us to explore wonders both on Earth and in the sky, from Africa to Australia. skyandtelescope.com/ astronomy-travel PHOTO: ROBERT GENDLER / ROBGENDLERASTROPICS.COM Sony α7 III Mirrorless Camera By Alan Dyer 44 Planetary Almanac 45 Messier 106 delights in this mosaic of Hubble and ground- based observations. 60 42 Lunar Almanac & Sky Chart Cover Story: 28 A Northern Run ON THE COVER S&T TEST REPORT BUILD COMMUNITY Seeking fellow enthusiasts? Find local clubs and observatories, or add your own organization to our listings. skyandtelescope.com/ astronomy-clubs-organizations EXPLORE THE NIGHT BLOG Follow Contributing Editor Bob King each week as he takes readers on an adventure through the night (and sometimes daytime) sky. skyandtelescope.com/king SKY & TELESCOPE (ISSN 0037-6604) is published monthly by Sky & Telescope, a division of F+W Media, Inc., 90 Sherman St., Cambridge, MA 02140-3264, USA. Phone: 800-253- 0245 (customer service/subscriptions), 888-253-0230 (product orders), 617-864-7360 (all other calls). Fax: 617-864-6117. Website: skyandtelescope.com. © 2019 F+W Media, Inc. All rights reserved. Periodicals postage paid at Boston, Massachusetts, and at additional mailing ofﬁ ces. Canada Post Publications Mail sales agreement #40029823. Canadian return address: 2744 Edna St., Windsor, ON, Canada N8Y 1V2. Canadian GST Reg. #R128921855. POSTMASTER: Send address changes to Sky & Telescope, PO Box 420235, Palm Coast, FL 32142-0235. Printed in the USA. A PR I L 2 019 • SK Y & TELESCOPE 22 Constellation Close-up: Centaurus and Crux

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