Witchhead Preliminary

So I have a few data sets that I haven't worked on from late 2018.  Part of the reason I haven't worked on them is that I ended up not taking darks or flats for a couple of the data sets.  Not taking darks is fine, but the idiocy of not taking flats is a problem.

I did take all the required calibration files for IC 2118 ('The Witchhead').   But I'm very rusty at PixInsight and it's taking a lot of time to get a good rendition of this target.   Along the way, I discovered an awesome tool that people have been using called, 'Starnet++'.   After a preliminary run at pre-processing, converted my Witchhead to 16-bit Tiff and threw it into Starnet++ and got the following:

There's still dozens of hours of processing to do, but I really like this early result "without" stars.   Once I eliminate all the obvious traces of stars (and the obnoxious line of satellite tracks), I can subtract the pre-Starnet image and generate a very good mask for stars.

126x5 min light exposures, 34x5 min darks, 40x110 sec flats, 51x1/4000 sec bias files.   Shot with at F/7.1 through a Tamron 150-600mm lens @ 300mm.

Upon closer inspection of the subframes, there is a fair bit of coma that starts around 50% from the center.   So the lens itself isn't the best, but I needed around 300mm to get this reflection nebula.

Before taking next steps on the processing, I need to go back and do a deconvolution on the image BEFORE I put it through Starnet++ again.

I probably have another 30-40 hours of processing to go.  :/

[Later: I also need to go back to DBE and try to address the orangish glow in the upper left.  That's definitely light pollution.   The original orientation of this nebula is 180 degrees which means the "top" is closer to the southwestern horizon.