This image covers the southern part of the Seagull Nebula (RCW 2, Gum 1 or Sh2-292 - 296) - a diffuse nebula visible on the border between the constellations Canis Major and Monoceros. The nebula is situated about 9 degrees to the northeast of the star Sirius and extends for two degrees to the NNE-SSW, in an area very rich in hot blue stars making part of the stellar association Canis Major OB1 to which it was initially assigned the abbreviation Canis Major R1 due to the presence of numerous reflection nebulae. Some of them are catalogued by Sidney van den Bergh in his VdB catalogue under different numbers (please see the annotated mouseover). A 3 panel mosaic (respectively an annotated mouseover) can be found just below: