Hi Lenny,

I am not familiar with the scripts that you are using. Maybe my version of PI is a bit old .
I am always a bit cautious of scripts especially batch pre-processing as if something goes wrong it is difficult to track it down.
I think that the problem is likely related to mismatching between lights and darks (you don't mention if you are using flats as these can introduce problems too). As Wouter suggests things like offset values being different can create the problems that you are seeing.
I think that pedestals can be useful to prevent clipping but clipping often is caused by problems in calibration. I have never found using a pedestal to help much in my image processing.

You may need to give more info. Is this a new problem? e.g. related to a change in your workflow or related to a new piece of equipment e.g. your quad band filter. Or has the camera always been associated with these issues?
The supplied image certainly looks strange. This is a single calibrated light frame, yes? Let us know how you process your darks in terms of calibration, gain, offset and exposure (are these consistent with your light exposures?). Do your uncalibrated light frames show any of these issues?
If the camera is new and this has been a problem from the start check Cloudy Nights or Stargazers Lounge as there may be other users who have encountered these problems and have solutions.

Mike

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