Hi Grady,

Well, I can see that there are numerous "stars" (for lack of a better name :-) scattered over the image. A lot of heavy image processing yields up a passible image. But is it real? Does it look familiar? I can't identify the field because I don't know the plate scale. All-Sky yields nothing. Your .jpg image is about 800x800, probably not the original sensor size of the FLI Proline. In any case, recreating the image doesn't answer your question.

Bad image5.jpg

There seem to be two different problems - the "shadowed" star images and the grey background. Both can be explained as the result of subtracting (or dividing) one image by another, in which the two images are not precisely aligned (horizontally
in this image).

Calibration might be a problem. The usual calibration step is an arithmetic division of the real image by the calibration image, but calibration would not normally generate a grey background. Were new calibration flats taken recently? New calibration masters might have been incorrectly created.

Were all of the images last night were bad, or just one series, or just one? Can you tell me where you were imaging? Otherwise, a problem in the camera readout?

A real conundrum right now. I'm sorry, this is not much help, either.