I had previously imaged M1 but with different equipment in a different location. When the team at SRO voted to do M1 I wasn't sure it would have anything new to say to me but the combination of a finer image scale (0.72"/pixel vs 1.1"/pixel drizzled down to 0.55"/pixel), more imaging time (43h 45m vs 13h 20m), better processing skills and the addition of BlurXterminator made a noticeable difference!

I also decided I wanted to explore a different palette for this image and so chose HOS rather than the SHO I used in the previous image. Also, as I was just getting ready to process this image the BlurXterminator tool was released and I decided to use this image as the first trial. In a word, I was impressed with what the tool could do! It does a great job of deconvolution.

We also endured some of the worst weather we've experienced at SRO in December 2022. Clouds, rain and snow basically consumed the first half of the month (and much of the second half as well but that's a story for another image). However, we were finally able to get our data and I started to process it.

Here's the workflow:

Each H, O and S:
dynamic crop
DBE

HOS:
channel combination
blurXterminator
noiseXterminator
SPCC (narrowband mode)
GHS
starXterminator (extracting unscreened stars)
LHE (2 scales)
MLT (very very mild sharpening)
pixel math in stars (screen)
dynamic crop (to final dimension)

stars
invert / scnr/ invert (to remove magenta)
GHS invert stretch

StarXterminator doesn't seem to work as well on linear data processed by BlurXterminator but it did well once the data was stretched. That's why I inverted the stretch on the stars after extracting them.

For color calibration I ended up using SPCC in narrowband mode rather than Color Calibration because I liked the results better. Normally I'd stretch the narrowband channels individually and then match the peaks after. However, BlurXterminator recommends combining the channels before running. I could then extract and then stretch individually but since each channel is fairly bright on its own I opted to go down this route.