Also known as NGC 6888, this emission nebula is 4700 light years away in Cygnus (the Swan). It is 20 arc-minutes across and powered by the bright star near center (WR 136). This is a Wolf-Rayet star that will go supernova in 100,000 years. The nebula is an expanding gas shell expelled 250,000 years ago when WR 136 was a red supergiant.
The image above was taken with the 4" Takahashi and ST-8E camera over 5 good nights from July 27 to Aug 5, 2008 at the Mistletoe Observatory. It is an RGB image (as detailed below) with a total exposure time of 6 hrs 50 min and a total number of exposures of 205. Calibration and alignment were done in MaxIm DL via custom scripts. Final contrast settings were done with Photoshop.
|Red||150 min||75 x 2 min||1x1|
|Green||120 min||60 x 2 min||1x1|
|Blue||140 min||70 x 2 min||1x1|
Previous image taken on July 18 and July 25, 2003.
The image above was taken with the 12" LX200, AO7, and ST-8E camera at f/6.3 on July 18 and July 25, 2003. It is an RRGB image (as detailed below) with a total exposure time of 1 hrs 30 min and a total number of exposures of 282. Calibration and alignment were done in MaxIm DL. RRGB layering was done with Photoshop.
|Luminance (red filtered)||1 hr||60 x 1 min||1x1|
|Red||~15 min||111 x 8 sec||2x2|
|Green||~5 min||37 x 8 sec||2x2|
|Blue||~10 min||74 x 8 sec||2x2|
Previous version taken on Aug 1, 2000 at the Mistletoe site.
This shot is a composite of twenty 30 second luminance exposures, and ten each 30 second Red, Green, and Blue frames. All frames were binned 2x2 at f/6.3 with the 12" LX200 and ST-8E.
Processing included "by the numbers" color calibration (1.15 : 1.00 : 2.05).