When should I use the Calibrate Mount utility? What does it do?

For Celestron’s German equatorial GoTo mounts, this feature is found in the menu under Utilities.

There are two functions in the Calibrate Mount sub-menu. Depending on exactly what mount you have and the hand control firmware version, the first one is called RA Switch or RA Index Calibration. The second function is GoTo Calibration.

RA Switch corrects for any error in the placement of index marks (Advanced VX, GT or CG-5, CGEM) on the mount housing. Or the position of the RA index switch inside the mount (CGE or CGE Pro). This will help the mount to more accurately find the two stars it uses for sky alignment when starting up an observing session.

RA Switch should be run when you are finished aligning the scope. It just needs to be done once, as the information is remembered by the mount’s hand control. Your next alignment will be easier once you’ve done it.

GoTo Calibration does just what the name says: it changes the final motions of a GoTo to compensate for imbalances cause by any heavy accessories attached to the scope to keep GoTo times short. It should be used whenever you are reconfiguring your scope and cameras, heavy binoviewers, guide scopes, etc. It is also remembered by your mount’s hand control.

Updated 12/4/13