Hey, thank you for your anwer!
I´ll drive the camera "directly" without additional gear ratio from the shaft.
For this I´ll mill an mount.
Because of using a 300mm lens, I don´t want the motor to stop and cause any vibrations or backlash.
In my thoughts it would step often enough for a smooth following of the earth rotation.
Thats the reason for the 1/16 stepping.
There are versions with additional worm gears, but I don´t have the machines to build an accurate one, so I first wanted to try my own thoughts.
Tell me if I have anything wrong.
Thank you!