Subject: IC1805 Heart [60'x60', M+6.50], Cassiopeia

Finally, a proper full-night clear sky (a few in a row even) with seeing conditions < 2". The first since I started the hobby. And my first proper long integrated exposure image, with the filter, on the new mount. I'm truly amazed at what came out. I like the not-so-red dominated palette due to the unmodded camera. In processing I used a background extraction, photometric colour calibration and stretches/(asinh) transformations, as well as a starnet++ recomposition where I destretched the dimmer stars significantly for a calmer image. This one is going on the wall for sure.

But boy did I mess around.

Astroberry / Ekos / KStars / INDI:
To control the camera and mount together remotely is the dream - and I had a raspberry Pi 4 laying around to try and give it a go over the past month. Of course someone built a linux distro for such a scenario, loving the open source community. Though Astroberry seems to be overdue an update for about 2 years, as its driver versions could not handle my .CR3 canon raw files. After many outdated incompatibility issues trying to compile updated drivers I decided to build on the latest raspbian myself, with great help from https://gitea.nouspiro.space/nou/astro-soft-build , encountering a few minor solvable linux issues.
I got the right cables and some velcro to set things up - the Pi can be powered from the mount with the right 15W 12V to 5V usb-c converter, and I had to use a USB hub before the mount was detected in Ekos. I was planning to put the pi on the mount and connect with my laptop wirelessly.

Polar alignment:
I was hoping my frustration with iPolar on OSX "not finding enough stars" would be helped with Ekos' alignment tool. The principle is very similar, but more customizable so stars were found and platesolved easily. But there was a learning curve here as well: after some wifi connection hickups, the canon driver getting stuck and needing a reset, Ekos freezing randomly a few times, and the tool failing with "could not detect mount rotation" sometimes, the process took well over a frustrating hour. I miss the direct optical feedback from the visual polar scope of the star adventurer... Every adjustment needs a 20-30 second wait for an update on the screen, while plate-solving needed to time out due to another streaked image, and I was getting freezing cold. Though - in hindsight I read that typical star adventurer polar alignment errors are ~6 arcmin, while after some trial and error I got it down to 0.5 with Ekos - better than needed at the moment. A second night things went faster already - with the mount closer to the router.

Focus:
INDI has drivers for the Canon autofocus to use it in Ekos - amazing. I played around with the step size / curve fits to get some experience - though it failed the fit quite a lot and never managed to get the focus better than my manual and extremely efficient bahtinov approach which landed me a half-flux radius (HFR) of 3.5 px on Polaris - it was always the lowest measurement point in the Ekos focus app. I think what didn't help were somewhat changing sky conditions - re-measuring the same focus point yielded somewhat different HFR values, hard to fit that... [Edit: could also be due to backlash in the focusing.]
At an undersampled imaging scale of 2.8 arcsec/pixel and 2" seeing, I guess I was hoping for the multi-measurement hyperbola fit to improve somewhat upon my manual focus to make sharper images. (Perhaps Polaris is too bright and gets saturated?). I find it hard to believe the glass quality of a canon L lens is the limiting factor, and diffraction limits should be below 2 pixels as well. In any case, the EF-RF filter adapter I use disconnects the lens focus control anyway, so I'll leave a proper configuration for later.

All in all, it's very nice to be able to put performance numbers to my setup with Ekos - it gives it a scientific edge.

GoTo:
After polar aligning I tried to GoTo with the KStars planetarium - but it quickly drove my mount into the ground with a horrible gear-gnashing noise. I couldn't stop it in the app as the wifi had difficulty staying connected - so I had to quickly power down manually. What a scare. I was cold and tired and left it for another day. After browsing fora a lot, the second day I figured out I had to set the 'home' position in INDI as well as on the hand controller - "plate-solving and synching" does not give Ekos the full mount orientation and for some reason it doesn't get it from the mount itself. After that GoTo in KStars worked great. Plate solved, and adjusted its position accordingly for perfect framing. Very happy to see that.

Exposure scheduling:
After the many struggles above I was a bit hesitant to use this for now - I guess I need to build up a trust relation with Ekos before I'll allow it to run my setup all night while I sleep. So I went with my manual 30s exposure looping using my reliable and cheap canon wired switch. It was a bit scary to leave the whole setup in the open while I went to bed, so just in case I covered the thing with a plastic bag with a hole in it for the lens.
I let it go from 12 to 5 am before I checked up on it, and switched targets to Bode's galaxy until dawn as the Heart was falling below my garden fence. The canon battery lasted the whole night in the freezing cold with the screen off, consider me impressed.

Edit: experimented with AstroClean (from AstroSharp) - this seems to smoothe the stat. bkg noise a bit.