Crescent nebula - narrowband

Crescent nebula

NGC 6888

 

This fascinating nebula is generated and illuminated by a large central star which is emitting huge amounts of gas.

This is a Wolf-Rayet star, and the gas is embedded at high velocity , and then runs into older layers of gas further out.

 

Be sure to zoom in or expand image.

 

Here's the description from Wikipedia: "The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It was discovered by Friedrich Wilhelm Herschel in 1792. 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."

 

Imaged from Deep Sky West - Rowe New Mexico, using RCOS 14.5 inch Ritchey–Chrétien telescope F/9,

 

13 hours result: Bicolor narrowband

Ha: 6 hours,OIII 7 hours.

RGB mapping Ha : 0.42Ha +0.43 O : O

Transparency and seeing very good to excellent, under moonlit skies even full moon for some frames.

September 10-19, 2016

 

Process in Pixinsight, and Lightroom.

SBIG 16803 CCD,AO-X

 

 

Done