JUPITER UPDATE: Amateur Findings in 2017 ABELL 194: A Whale of a Galaxy Cluster OBSERVING CHALLENGE: Compact Galaxy Groups PAGE 52 PAGE 58 PAGE 34 THE ESSENTIAL GUIDE TO ASTRONOMY The Race to MARS Four Missions, One Launch Year, and Why We're Crazy About the Red Planet PAGE 14 The Mysterious Lunar Event of 1794 PAGE 30 Tarantula Nebula: Snapshot of a Star Factory PAGE 24 Test Report: Celestron's CGX Equatorial Mount PAGE 62 NOVEMBER 2017 Tips for Imaging Under Dark Skies PAGE 68 skyandtelescope.comhttp://www.skyandtelescope.com