This is a very deep image using a large telescope that highlights the gas clouds surrounding NGC6888 (as well as enhancing the details of the nebula itself).
NGC6888 was formed by the fast
stellar wind from the
Wolf-Rayet starWR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a
red giant around 300,000 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.
There are 5 versions of this image that each highlight different aspects of it's dynamic processes:
NGC6888 (Crescent Nebula) in SHO, with stars:
https://www.astrobin.com/q63lr3/NGC6888 (Crescent Nebula) in SHO, no stars:
https://www.astrobin.com/q2dgmw/NGC6888 (Crescent Nebula) in Ha, no stars:
https://www.astrobin.com/82yuss/NGC6888 (Crescent Nebula) in O3, no stars:
https://www.astrobin.com/l3zaei/NGC6888 (Crescent Nebula) in S2, no stars:
https://www.astrobin.com/4eu4dn/
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