PI's BatchPreprocessing script seems to be introducing a gradient across the top of my blue (and to a lesser degree, green) masters that is not present in any of the subs and that cannot be removed or mitigated by flat subtraction, DynamicBackgroundExtraction or other means. I am using an SBIG STT-8300M camera and FW8G-STT filter wheel. The filters are all firmly seated and perpendicular to the focal axis of the camera, and the problem occurs regardless of the rotation of the camera, the condition of the sky, temperature, binning or any other hardware or environmental variable.
I attach a JPEG file showing my PI desktop tiled with the four L, R, G and B masters generated by the BatchPreprocessing script from recently captured eight each 300 second R, G and B exposures and twelve 600 second L exposures. None of the four masters you see on the attached JPEG has been post-processed in any way following their creation by the BatchPreprocessing script. You can see very clearly the wide band across the blue and green masters. This band does not appear in the raw subs and I conclude, therefore, that it is an artifact created by the BatchPreprocessing script or one of its sub-processes.
I have tried every tool in PixInsight to try to remove this gradient without success and am at my wit's end.
I would very much appreciate any suggestions as to what I might do to prevent or to remove it.
Thanks,
Jay Butler
