Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2013 November 23 Comet ISON from STEREO Image Credit: Karl Battams, NASA, STEREO, CIOC Explanation: Still intact, on November 21 Comet ISON (C/2012 S1) swept into this animated field of view (left)..