Our knowledge of the Veil Nebula or Cygnus Loop extends back to antiquity. Cygnus (which means ΓÇ£swanΓÇ¥ in Greek) is one of the few constellations we are certain was studied by ancient Greek and Egyptian astronomers. Cygnus is listed in the book Almagest, by Ptolemy, who lived in Alexandria, Egypt, between A.D. 100 and 151. One of the first astronomical compendiums, Almagest was based on an earlier star catalogue compiled by Hipparchus around 140 B.C.
