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 Friedrich Wilhelm 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. [Wiki]
Data source Davide Coverta |
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| Optic |
RC8 f/6 |
| Camera |
QSI 683 WS |
| Filters |
Astrodon Ha L, R, G, B |
| Mount |
NEQ6 with EQASCOM
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Guide
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OAG with Lodestar
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Frame center
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RA 20:12:16 DEC 38:18:54 J2000
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Date
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30th July 2018
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Site
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Astrobioparco di Felizzano, AL, Italy
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| Exposures
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Ha - 22x1200s @-15C bin 1x1
L 22x900s bin 1x1
R 6x600s bin 2x2
G 6x600s bin 2x2
B 6x600s bin 2x2
Integration time - 15h50m
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