My last image of the crescent nebula was in 2006 so about time for an update! Taken over several nights in August with the emphasis on Ha and Oiii with the addition of RGB stars. This image is cropped a little as I had problems flat fielding which I now think I've sorted. The spectrum was taken during my 'Spectroscopic phase'
with the Staranalyser 100 back in 2008 of the Wolf Rayet star at the centre of the nebula and responsible for this very popular summer target.
Hope you like it.
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 William 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.
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