NGC6888

NGC6888 - The Cresent Nebula

The final revision where the oxygen shield that covers the nebula is visible.

BI-Color, Ha for Red, OIII for green and blue

Bi-Color with RGB stars from an old DSLR image

Ha

Superluminase

R2-HA

Telescope

Boren-SImon 8" F3.6

Imaging Camera

Starlight Xpress H9 Mono

 

 

Exposures :

37*600 Ha

 

20*600 OIII

 

5*1200 OIII

 

 

Reduser/Corrector

ASA 2" x 0,73 Corrector/Reducer 2KORRR

FIlters

Astrodon H-alpha 6nm

Astrodon OIII 3nm

Date

September. 2014

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.

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.(WIKI)