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Monday, September 9, 2013

Sh2-112, processed with an additional data



I'm waiting to start imaging a new material but there are few items in factory service and I'll need to wait them to come back. Mean while I reprocessed my image of Sharpless object 112 in constellation Cygnus. 

Originally I had too little exposures to reveal the background nebulous properly. I noticed, that I actually have a very deep exposures for this object but taken with very different image scale. I have shot this area with a Canon EF 200mm f1.8 optics and the background nebulous stands out very nicely there. 

I have developed a new method to combine data from very different sources. It's based on signal to noise analysis, a very weak signal doesn't usually has too much details in it. The weak signal from a low resolution source can be used with a high resolution signal and best of both image types will be used in final image.

Original versions of images bellow can be seen in this blog post:
http://astroanarchy.blogspot.fi/2012/12/sharpless-112-sh2-112_5.html

Sharpless 112
An emission nebula in constellation Cygnus

Image in mapped colors from the light emitted by ionized elements. 


Red=Sulfur, Green=Hydrogen and Blue=Oxygen.


The additional data is taken from this wide field image of the same object


This is a small part of a very large mosaic image of the constellation Cygnus, the mosaic can be seen HERE.
Sh2-112 is located at lower center of the image and the weak background nebulae stand out clearly. Image is shot with a very fast opticla configuration, a Canon EF 200mm f1.8 lens at full open, a cooled astronomical camera, the QHY9 and the Baader narrowband filter set. Total exposure time for this image is around 4h.

Sh2-112 in visual spectrum

Image is in visual colors, combined from the narrowband data.


Technical details:

Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Levels, curves and color combine in PS CS3.

Optics, Meade LX200 GPS 12" @ f5
Camera, QHY9
Guiding, SXV-AO, an active optics unit, and Lodestar guide camera 8Hz
Image Scale, ~0,8 arc-seconds/pixel
21 x 1200s exposures for the H-alpha, emission of ionized Hydrogen = 7h
3 x 1200s exposures for the O-III, emission of ionized Oxygen = 1h
3 x 1200s exposures for the S-II, emission of ionized Sulfur = 1h

Additional exposures for the background nebulae are shot with a very fast opticla configuration, a Canon EF 200mm f1.8 lens at full open, a cooled astronomical camera, the QHY9 and the Baader narrowband filter set. Total exposure time for this extra data is around 4h.




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