The Crescent Nebula

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About this Image

Subject	The Crescent Nebula
Objects	NGC 6888 AKA Sharpless 105, WR 136 AKA HD 192163
Info	Wikipedia entry
Data	SAO/NASA Astrophysics Data System (ADS) database entry
Description	Spectral band image of Crescent Nebula. Red = Hydrogen Alpha, Green = synthetic Hb+O3, Blue = O3. The Crescent Nebula is a form of planetary nebula where the nebula has been created by the fast stellar wind from the central massive star impacting with it's previously ejected outer shell from the red giant phase. The central star is a Wolf-Rayet star - these are massive stars that burn through their fuel at a prodigous rate. They are the James Dean's of stars that live fast and die young!

Date	20100912-20101205
Location	Pumpkin Patch Observatory, Bourn, Cambridge, UK
Optics	Astro Optik 400mm Cassegrain @ Cassegrain focus (f=3600mm)
Filters	Astrodon 6nm narrowband, YR Cyclops filter wheel
Mount	Paramount ME
Guiding	MOAG/SBIG ST402ME
Camera	FLI Microline 16803
Exposure	Total exposure 22.8hrs - R/Ha 8.3hrs, Synthetic G = Ha*.3+OIII, B/OIII 14.5hrs, 20 and 10 minute subs
Processing	Maxim/DL 5, CCDStack, Photoshop CS
Notes	Green channel is made up of a synthetic Hb created from Ha 30%, and OIII at 100%;