jlheely
Crescent Nebula, Bi-color
The Crescent Nebula (NGC 6888, Caldwell 27, Sharpless 105): an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 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.
Imaged August 26, 2017 in bi-color. 3 hours in Hydrogen-alpha (mapped in red channel), and 3-hours in Oxygen-III (mapped in blue and green channels). ES 102mm refractor with 0.8x focal reducer (571mm effective focal length), ZWO ASI 1600 camera at -10C.
Crescent Nebula, Bi-color
The Crescent Nebula (NGC 6888, Caldwell 27, Sharpless 105): an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 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.
Imaged August 26, 2017 in bi-color. 3 hours in Hydrogen-alpha (mapped in red channel), and 3-hours in Oxygen-III (mapped in blue and green channels). ES 102mm refractor with 0.8x focal reducer (571mm effective focal length), ZWO ASI 1600 camera at -10C.