Under most normal circumstances that would be the best way forward. For a telescope drive, where backlash and mechanical hysteresis are significant error sources, and gear periodic errors also have to be taken into account, then a high reduction box is not a good idea, hence the need to use torque motors.

It all depends on the pointing error Zhang can decide he can tolerate for his telescope really. If its a little scope, its much easier to use a microstepper.

Steve