I think I have succeeded in getting our OnStep build to work properly. Previously, whenever I asked the drive to slew to an new location, the stepper motors would build up to a certain speed and then stop rotating while they screamed, seemingly in protest. It’s called stalling.
With the help of several of the principal leaders in the OnStep project (Howard Dutton, Ken Hunter, Khalid Bahayeldin) and Alan Tarica and Prasad Agrahar, I think I may have finally got the settings set properly. The final secret was to reduce the slewing speed in the smart hand controller to the lowest setting.
This does make slewing rather slow, however. To go from the location of Jupiter to Capella tonight, which is a pretty long distance across the sky, took nearly eight minutes. Watch the video.