The Crescent Nebula (NGC 6888 or Caldwell 27) is an emission nebula in the Cygnus constellation, about 5000 light years away. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray emitting temperatures.
Taken at around 1.30am through a William Optics FLT 110
with a Canon EOS 1000D Modded with LP filter.
10 x 5min subs at ISO 800 6x 5min darks stacked in DeepSkyStacker and final
processed in Photoshop.
