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 |