Ok, this morning I tried the microscope webcam again. The overexposure with the moon is a bit of a problem...
But yeah, it is not a planetary webcam.
I also tried prime focus with my Nikon and a program that connects it to the computer like a webcam. That WAS good. No overexposure, good focus. Unfortunately though the camera is a bit heavy. I mean, the mount holds it fine, but I had the moon on the screen and when I wanted to take a shot... it had already slightly come down and it was not centered any more. This was not because my mount can't track, it was really a matter of 2 seconds...
Now that I have seen it is good I will make more experiments also during the day. I do realize it is an Alt-Azimuth mount for beginners though.
I was really pleased with my Nikon and would like to make good use of it.
Update: The Nikon was great also during the day.