The Crescent Nebula, which lies in the constellation Cygnus the Swan, has plenty of names. Among them are NGC 6888, Caldwell 27, Sharpless 2–105, and LBN 203. Whatever you call it, this object is a fascinating bubble of gas being carved out of the interstellar medium by the winds of an intensely hot star named WR 136.
As this high-velocity wind hits a slower-moving stellar wind that the star previously produced when it became a red giant, the collision produces a shock front and the shel