Advertisers in This Issue Astronomy equipment manufacturers and dealers are a valuable resource for amateur and professional astronomers alike. Patronize our advertisers in this issue and enjoy all the benefi ts of their expertise. Product Locator Astro-Physics, Inc. »page 81 telescopes / mounts astro-physics.com Celestron »page 5 binoculars / eyepieces / mounts / telescopes celestron.com Diffraction Limited »page 1 cameras diffractionlimited.com iOptron »page 67 mounts / telescopes ioptron.com Sky-Watcher USA » page 73 + inside front cover binoculars / mounts / telescopes skywatcherusa.com Software Bisque »page 3 + back cover mounts bisque.com Stellarvue »inside back cover eyepieces / telescopes stellarvue.com William Optics »page 75 eyepieces / telescopes williamoptics.com Ad Index Arizona Sky Village Portal ......................... 81 Astro-Physics, Inc. ................................... 81 Astronomical League ............................... 81 Bob's Knobs ............................................. 80 Bradford Exchange .................................. 79 Casitas de Gila Guesthouses ................... 81 Celestron................................................... 5 Cosmonauts do it in Heaven ..................... 80 Diffraction Limited ..................................... 1 DiscMounts, Inc. ...................................... 81 Insight Cruises ......................................... 75 iOptron .................................................... 67 Knightware .............................................. 81 Lunatico Astronomia ................................ 80 NexDome ................................................. 81 Nine Planets Ring .................................... 81 PreciseParts ............................................ 80 Revolution Imager .................................... 80 Sky & Telescope ................................ 67, 83 Sky-Watcher.......................................73, C2 Software Bisque .................................. 3, C4 Stellarvue ................................................ C3 Technical Innovations ......................... 80, 81 William Optics .......................................... 75 To advertise in our Product Locator, please contact Tim Allen at 773-551-0397, or email him at Ads@skyandtelescope.org 82 AUGUST 2021 * SKY & TELESCOPEhttp://www.astro-physics.com http://www.skywatcherusa.com http://www.bisque.com http://www.celestron.com http://www.diffractionlimited.com http://www.stellarvue.com http://www.williamoptics.com http://www.ioptron.com