Bad gradient- again

Bruce Donzanti

Bringing up an old and aggravating issue- a bad gradient on my LRGB frames using WBPP.  When I manually performed star alignment and image integration for each channel, the gradient is not present, only slight vignetting and a few dust motes, as expected.  And I can create a reasonable image. So, I am concluding it is not an issue with the light frames per se, nor with WBPP, but rather something might be wrong with my darks and/or dark flats.  I did make new ones by covering the end of the scope for the darks and a Alnitak flat light panel for the flats and dark flats. When this came up in the past, we discussed possible light leak, but I cannot find anything after repeated checking the scope from end to end.  When I look at the individual darks and flats, they seem normal.  Could it be the camera needs to be completely covered when making the darks? Or, skip the panel and use the sky?  I am open to any suggestions at this point.

Thanks,

Bruce  

Bruce Donzanti

Here is a screen shot of my master dark which I just noticed a gradient.  I do not see this gradient from my other camera on another scope.  So, perhaps this is the cause of the problem.

   

BlockHead

Cameras are not light tight. (no camera, period).

I always say that darks should only be taken at night and away from any sources of light. 

You did certainly discover the issue.

-the Blockhead

Bruce Donzanti

Thanks for confirming.  Another lesson learned.