

I also used these videos to try out PlanetarySystemStacker, a new stacking software that seems quite good to me, probably at least on a par with Autostakkert: https://github.com/Rolf-Hempel/PlanetarySystemStacker (There is also a thread on CN about it.)
After this quick test I think it may even give a bit better results for parts of the solar surface with low contrast (e.g. the rim of the disk), but I've only used it for a few images so far. I'll try it out some more as soon as the weather allows.
Kind regards,
Frank