GALLERY S BILLION-YEAR TANGO Warren Keller and Michael Selby Arp 245 in Hydra comprises the two interacting spiral galaxies NGC 2992 (center) and NGC 2993 (center left). The encounter is producing the tidal dwarf galaxy above NGC 2992, which is designated Arp 245N. Galaxy FGC 938 is seen to lower right of the interacting pair. DETAILS: Officina Stellare RiDK 500 and RiDK 700 Dall-Kirkham astrographs equipped with FLI ProLine PL16803 LDR cameras. Total exposure: 31.5 hours through LRGB filters. Gallery showcases the finest astronomical images that our readers submit to us. Send your best shots to gallery@skyandtelescope.org. See skyandtelescope.org/aboutsky/guidelines. Visit skyandtelescope.org/gallery for more of our readers' astrophotos. 78 JUNE 2 021 * SK Y & TELESCOPEhttp://www.skyandtelescope.org/aboutsky/guidelines http://www.skyandtelescope.org/gallery