Quote:
Originally Posted by Ric
Very nice images Dennis.
I noticed on M83 that the middle to upper left seems lighter. I get that as well on some of my images, is that light pollution being captured as well or something else.
Cheers
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Hi Ric
The M83 image has not been “reduced”, that is, Flat Fields and Dark Frames were not taken and applied. A Dark Frame (subtracted) removes thermal noise and a Flat Field (divided) removes light gradients, vignetting, dust spots, etc.
The light gradient would have been removed if I had taken a Flat Field. The DSO’s were captured using the Celestron F6.3 Reducer/Corrector. When using the F6.3 R/C, vignetting becomes quite apparent, even on a 640x480 chip.
Cheers
Dennis