Dec 312010


This is the Crescent Nebula (NGC 6888) in the constellation Cygnus (The Swan).  The bright star in the center of the picture (HD 192163), known as a Wolf-Rayet star, is a massive star nearing the end of its life.  Earlier in its elderly life the star became a red giant and shed its outer layers into space at the relatively slow speed of about 20,000 mph.  A subsequent event, powered by deeper more energetic layers, ejected gas at the much higher speed of about 3,000,000 mph.  What we see is the second wave of gas running into the first and ultraviolet energy from the stars core causing the piled up gas to glow.  This is all a precursor to a future supernova.

 The Crescent Nebula is about 5,000 light years(Ly) away and is about 18Ly by 25Ly in size.

 This nebula is a fairly faint nebula.  The image is a stack of 120 30-second exposures (L:30x30s,R:30x30s,G:30x30s,B:30x30s).  With only 30-second exposures the image only shows the brightest part of the whole nebula.

As with most of my images North is to the right and East is toward the top.

 Posted by at 13:07  Tagged with:

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