Celestron R/A Single Axis Motor Drive for the AstroMaster Telescope
Compatible with all German Equatorial (EQ) AstroMaster and PowerSeeker telescopes. If the mount is not polar aligned, the drive will not appear to work correctly.  This motor drive attaches to the gear shaft of the mount using a coupler with a set screw.  If the set screw is not tightened, the motor could slip and not drive the telescope properly.