Greg Meyer from Phoenix, Arizona; taken near Ash Fork, Arizona Dreyer’s Nebula is a blue reflection nebula roughly 2,700 light-years away in the constellation Monoceros; its blue color comes from nearby hot stars, whose light is scattered off of dust. Dreyer’s Nebula was accidentally recorded in the Index Catalog twice, as numbers 447 and 2169.Continue reading "Dreyer’s nebula"