NGC6888 Crescent Nebula

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 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. (Wikipedia)

 

Narrowband image: 29/4 & 11/5/15

Oxfordshire, UK

4 Hours Total Exposure

Bin 1x1: 6x1200s Ha

Bin 2x2: 7x600s SII, 5x600s OIII

 

Equipment:

T: Takahashi FSQ106ED

C: QSI683ws Mono CCD, Astronomik Filters (6nm Ha)

M: Celestron Advanced Vx

G: QHY5-II

 

Acquisition and Processing:

PHD2, Sequence Generator Pro, CCDStack2, Photoshop CS6

Done