I just got a camera (QHY 16200A) with overscan capabilities, wanted to check my understanding to see if I have this right:
Previously I created a master bias according to the Light Vortex tutorials with a camera that did not have overscan. I should be able to use the overscan capability to do better bias correction for an image. Because the bias is dependent on the state of the (non-cooled) components in the camera, overscan provides better correction than a master bias frame from an average of a bunch of rapidly acquired bias images.
The bias for a given image is determined by taking the overscan region, averaging columns and fitting a smooth representation of bias *along* the columns. This is done for *all* images (lights, darks, flats). The master bias (now the zero frame) is also corrected this way. The zero frame is still subtracted from darks, flights and flats the way the original master bias would have been. All of this is done simply by specifying the overscan regions in BatchPreProcessing.
Is that right? I am not sure what the 'target' region is in the overscan region specification. Does using the overscan region provide materially better accuracy than simply making a master bias out of a quickly acquired set of bias frames?
