In another thread it was suggested that I could use an absolute encoder to get around having no way to "home" a stepper setup. I did some googling and figured out that I'd need either an electric motor with a multiturn absolute encoder attached (stepper or DC) or a ready made servo motor with the same sort of encoder.

The motor would need to be quite small and wouldn't have to be very powerful. It only needs to turn a telescope focusing knob which is very easily turned with two fingers and a light touch.

Would anyone know of such a beastie and where to get them? I did find some that would probably work but they're quite a bit more powerful than I need and >$400 US each.