More Van Gogh ears

So it was not just the really short exposures that are giving me the "ears". This is a combine of a bunch of 5 minute exposures with an H-alpha filter. Camera temperature was -40C. Dark subtract was with a sigma-combined set of bias frames and 3 minute darks at -40. Flat field was another sigma combine of about 10 frames with the Ha filter done at dusk. Looks like both flats and darks could be a bit better, however, still have those one-sided ears showing up. I have an idea as to what this is and how I can fix it, but wanted to hear other thoughts before I dive into uncertain waters. Thanks to anyone who can confirm (or deny) my suspicions.

Charlie

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