MIND THE GAP: GALACTIC HULA-HOOP: OBSERVING: How Planets Are Built Hoag's Object A Cascade of Galaxies PAGE 34 PAGE 57 PAGE 22 THE ESSENTIAL GUIDE TO ASTRONOMY MAY 2020 ASTEROID RECON SURPRISES from Ryugu and Bennu Page 14 skyandtelescope.org The Untimely End of Amateur CCDs? Mitchel's Mountains on Mars The Discovery of Jupiter's Moons Page 30 Page 52 Page 60http://www.skyandtelescope.org