M81 captured from a dispersed campsite near Bryce Canyon National Park on 25 April 2022. This was my first serious attempt at deep sky astrophotography; previously I had mainly done satellite tracking and some planetary. The hardware and software and weather all cooperated for the most part. I'm quite pleased with this result.

All the hardware was controlled using Ekos during the capture, and it worked well mostly. I definitely need to learn more about how to get the best performance out of the autofocus and autoguiding modules but they both worked reasonably well especially considering the limited amount of practice time I had with the software before doing this capture.

Processing was done entirely using Siril 1.1.0. I did calibration using darks and bias frames (but no flats). Global registration. Manually rejected a couple frames with satellite trails that were not being rejected by the stacking clipping algorithm for some reason. Tried to use the fancy Photometric color calibration that reviewers rave about but it kept failing for me saying no stars were suitable. Maybe all the bright stars that are in their catalog are saturated in my RGB composit? I didn't figure it out, so used the un-fancy color calibration. That was followed by a round of asinh transform followed by several rounds of histogram adjustments and cropping. Finally I downsampled by 2x in each dimension and exported the JPEG version here.

The main flop from this trip is that my approach to taking flats did not pan out. I tried to use a technique suggested by Thierry Legault in his outstanding book Astrophotography where I placed a piece of white fabric in an embroidery hoop over the aperture and then set off a cheap-as-dirt camera flash by hand during the flat exposure. Unfortunately each one of these exposures looked a little different, and not just a difference in global brightness. I suspect that the camera flash was not illuminating the fabric uniformly. When I tried to use these as part of calibration they just made matters worse rather than better. After abandoning the flats I tried to use background extraction in Siril to compensate for the vignetting but that also seemed to make things worse. I also tried just cropping to a smaller region but I thought the composition looked better with a larger star field around the galaxy. Ultimately I just accepted that there is some uncorrected vignetting in the background and tried to hide it by histogram adjustments and that seemed to work well enough.