Well, I finally did it. I impulse bought PixInsight.
Everyone says that this is the ultimate astrophotography processing software. I got it because I’m mostly interested in improving my backgrounds and noise reduction. It’s much more flexible and powerful than Siril or GIMP. I really liked those programs, but I have much more freedom to experiment and combine different things to process an image.
As an experiment, I took my recent integration of M81 and M82. It was about the only linear stack that I’ve kept recently. I mostly just wanted to play around with some of the new tools, like PSF deconvolution, dynamic background extraction, and TGV denoise. I will say that the results are far superior to anything I could create in Siril and GIMP.
Here is the same original linear integration from my original take on these targets, but completely processed in PixInsight. I was able to improve the bad background caused by reflections and light leaks in the telescope. I was also pleased with how the deconvolution sharpened the image, though it ruined some stars without me noticing. I was thankfully able to fix the stars later in the process. The TGV denoise and multiscale linear transforms really toned down the noise without ruining details or making it look “plasticy.” The iterative morphological transform is wonderful for toning down the bright stars after stretching. I may have gone a little hard on the saturation, but I do love me some color.

PixInsight also has a nice astrometry plugin that includes the PGC catalogue, something I’ve really been wanting to include in my posts. This catalogue lists many small, distant galaxies that you can typically see in my better integrations.

Overall, I am very happy with my purchase of this software. I’m sure that as I learn the tricks and details for the tools, my image quality will drastically increase.
And thank you, PixInsight, for making this available for FreeBSD!