CMOS HSO data from Telescope Live in Spain
NGC 6888 is also known as the **Crescent Nebula**¹²³. It is an **emission nebula** in the constellation Cygnus, about 5,000 light years away from Earth¹². It was discovered by **William Herschel** in 1792¹.
NGC 6888 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 ago¹. 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 temperatures¹.
NGC 6888 has a diameter of about **25 light years** and contains several bright filaments and folds of gas¹². It has an apparent magnitude of **7.4** and can be seen with binoculars or a small telescope¹². It appears as a diffuse patch of light near the bright star Lambda Cygni¹². It is best seen from the northern hemisphere during summer and autumn months².
Kilde: Samtale med Bing, 18.6.2023
(1) Crescent Nebula - Wikipedia.
https://en.wikipedia.org/wiki/Crescent_Nebula.
(2) APOD: 2021 June 17 - NGC 6888: The Crescent Nebula.
https://apod.nasa.gov/apod/ap210617.html.
(3) NGC 6888: The Crescent Nebula | Science Mission Directorate.
https://science.nasa.gov/ngc-6888-crescent-nebula.
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