Crescent Nebula Area.......

Crescent nebula area.......

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 William 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[citation needed] 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.

Location: Stinger of Scorpius Observatory, Filiates, Thesprotia - Greece.

Work in progress.....

Bortle Scale: Class 4

Constellation: Cygnus

Imaging Telescope: William optics star 71 f/4.9

Equatorial Mount: Avalon linear fast reverse (Avalon Instruments)

Guide Scope : Skywatcher ed80 Black Diamond

Guide Camera:ZWO ASI290MM Mini (mono)

Main Camera: CCD Atik One 6.0 Monochrome

Filters: Astrodon Hydrogen Alpha 5nm

Exposures: 45X600sec for Hydrogen Alpha : (7.5 hours total)

Binning: 1x1

Image Calibration: 60 dark frames, 230 bias frames, 35 flat frames

Sensor temperature: -10°C

Image acquisition software: Artemis Capture

Telescope guiding software: PHD2

Processing software: Pixinsight - CCD stack - Photoshop CS6

Acquisition dates: 05/06/2021 - 29/06/2021 (H-Alpha Filter)

Total exposure : 7.5 hours