Astronomy Picture of the Day . ... To the eye, this cosmic composition nicely balances the Bubble Nebula at the lower right with open star cluster M52. ... The Great Nebula in Orion, also known as M42, is one of the most famous nebulas in the sky. ... Tisdale 2 Rock Formation on Mars . ... Sweeping through planet Earth's night sky, last weekend Comet Garradd (C/2009 P1) visited this lovely star field along the Milky Way in the constellation Vulpecula. ... J102815: A Star That Should Not Exist . ...