I will add another question...this has been discussed before, but I can't seem to find an answer in the threads. I generate master flats, darks, bias frames from FITS format using SGP and I generate XISF files. When I try to run the batch preprocessing script, it looks in the FITS header for the file type. The FITS header is destroyed by generating the master files and all that's left is history labels so the script generates an error. I have been using single flat frames to get around this. Is there a better solution?