Crescent nebula (Cygnus Constellation)

La nébuleuse du croissant dans la constellation du Cygne (NGC 6888)

DESCRIPTION

The Crescent nebula (NGC 6888 or Caldwell 27) is an emission nebula in the Cygnus constellation, about 5000 light years away. 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 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.

Credit : APOD and Wikipedia informations

ACQUISITION

 

Date & Location

15, 16, 21 Juillet 2010 – Lozère, France

Telescope/Optics

Takahashi FSQ 106ED

Mount

Takahashi EM200

Camera CCD

SBIG STL 4020M

Focuser

Robofocus/FocuxMax

Filters

Ha/SII/OIII Astrodon filters

Guidage

Off-axis MMOAG (Astrodon) STL remote guider TC-237H

IMAGING PROCESS

 

Exposures

Ha(13*15min) SII(13*15min) OIII(13*15min)

Total : 9h45

Out temperature : 16°C

In CCD temperature : -20°

Softwares for acquisition

Robofocus, Focusmax, CCDsoft V5, TheShy6 Pro, CCDAP 4, CCDInspector

Softwares for digital image processing


Calibration, Registration, Color stack with CCDstack 1.0 (CCDIS plug-in)

Full processing with PIXINSIGHT Core version 1.6


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