@geehalel: first off, many thanks for your help, which I appreciate very much. Regarding the communication problems with my AZEQ-6: I guess something went wrong on my system with the compilation of your branch of the libindi. After com problems with other devices I reverted to the current official libindi by just following the compilation instruction on the github page. After that I could connect again with the eqmod and other drivers (not with the alt-az driver, though). Any ideas what might have caused the problems ? I have I relatively clean install with all recent updates of astroberry running on a pi4. The only amendments done to the astroberry is an installation of a wifi dongle. The compilation process did finish without any errors in both cases, i.e. installing your branch and the official one.
Regarding the alt-az drivers: I have not been aware, that these drivers implement kind of leapfrog tracking. Probably for the planetary imaging I would be better of to revert to the factory driver running off the handcontroller. Once this is initialised and aligned I can connect with the synscan driver. The only thing which put me off here, is that I first have to do the manual align according to the synscan manual as the driver will not accept any input before conclusion of the initial alignment routine. I would have to install and use the visual guide scope, which I retired already and every time punch in the current date, time & stuff. It sounded so promisingly easy to do all the alignment with with ekos alignment module.
So if there currently is no decent alternative to the factory drivers I would also pitch again for having some form of an alternative for alt-az control. As much as I understand the benefits of GEM mounts, the recent advancements with EAA made many things possible, e.g. live stacking of relatively short exposures, which makes DSO much simpler as one does not necessarely need guiding and even field rotation is not a problem as the image is being de-rotated by software. I happily volunteer for testing !
The big advantage of the alt-az mounts is the time you save when setting things up. You just have to level the base of the mount and are ready to go. Setting up my stuff in GEM config takes considerably more time: in my case I have to go to my backyard as the view of Polaris is obstructed from my terrace. The tripod for my alt-az mount has rollers attached, so I can just roll the entire rig out, level it and start. I am only a casual observer. So when i have lets say three hours for observing during evening hours, I loose 1 hour for mounting and dismounting my equipment and probably 20 min. for proper alignment of the scope. Something always goes wrong, so in the end I have max. 50% of the time for actual observing. With the alt-az I would just roll in and out in 10 minutes and have the scope aligned in 5 min. So effectively the time for observation is doubled. At least in theory...
Anyway, I would very much appreciate to have a system as good as eqmod for the alt-az mount. With the advancments in EAA I would guess that more and more people will use alt-az mounts as they are simpler to use and can bring more people to this fascinating hobby.