| 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] |
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| Optic |
SW ED80 + 0,85 Reducer/Flattener |
| Camera |
Atik 383L+ |
| Filters |
Baader Ha 36mm |
| Mount |
NEQ6 with EQASCOM
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Guide
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SW 70/500 with AlCCD5
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Frame center
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RA 20:12:11 Dec 38:19:52 J2000
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Date
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2016/07/17
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Site
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Backyard, Busto G. Milan, Italy
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| Exposures
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Ha 8x900s @-10°C
Integration time - 2h
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Notes
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First imaging session with my new semipermanent observatory
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