SPIRAL GALAXIES: Running on Empty CONSTELLATION CLOSE-UP: Centaurus and Crux WORKBENCH: Four-Mirror Binoscope PAGE 14 PAGE 22 PAGE 72 THE ESSENTIAL GUIDE TO ASTRONOMY Northern Messier Marathon the Challenge PAGE 28 Nurture Your Newtonian: Collimation PAGE 68 TEST REPORT: Sony's α7 III Mirrorless Camera PAGE 60 Galactic Cirrus: Follow the Clouds PAGE 57 APRIL 2019 skyandtelescope.comhttp://www.skyandtelescope.com