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.
It is a rather faint object located about 2 degrees SW of Sadr. For most telescopes it requires a UHC or OIII filter to see. Under favorable circumstances a telescope as small as 8cm (with filter) can see its nebulosity. Larger telescopes (20cm or more) reveal the crescent or a Euro sign shape which makes some to call it the "Euro sign nebula".....
And now back to "us"...
This is a reprocess of an earlier version of this object i shot back in summer of 2013 from Drassa.
I was not very pleased by the first result as the integration time is really low so i dedicated a little more time on it.
Total exposure is just 0.8 hours (5x600 second shots) with respective calibration frames.
OTA:Skywatcher Equinox 80 ED (with no field flattener.
....I need to integrate more time on this jewel...this area of the sky is simply fantastic for wide field photos.
By clicking on the picture you may view the higher resolution version.