Motor control solution on the truntable for computer vision and optics usage
I once used a spectrometer that was just a grating on a rotation stage.  It had a worm gear drive and a stepper motor turning the worm gear.  Given different worm gears and stepper motrs you can get very fine resolution.  The problem is then repeatably.  There is gear back lash which can be removed by always going in the same direction.  And then finally you'll need a way to set a zero point.  For the spectrometer this was done by observing the zeroth order reflection from the grating.  You could do a similar optical thing.  Or perhaps a mechanical limit switch.  Once you have zero getting to any angle is just a matter of counting pulses into the stepper.