The Crescent Nebula, or NGC 6888 is a rather faint emission nebula in Cygnus, located about 5,000 light years from earth. 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 250,000 to 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.
|Scope||Explore Scientific 127ed APO refractor|
|Guiding||St-i through a Zenithstar 80mm refractor|
|Exposure Info||43 X 15 minute exposures for a total exposure or 10.75 hours It was imaged over several nights between 10/30/2018 and 11/5/2018.|
|Date||October 31, 2018|
|Copyright||Photo copyright Thomas Kerns, Beluga Lake Observatory|