Re: Difference between Recalibrate and Sync

Roland Christen

Recalibrate: when you send the mount to an object via keypad or planetarium program, the mount receives RA/Dec co-ordinates for that object and stores them in the memory. Now as you center the object, the internal co-ordinates change slightly because you moved the mount via the buttons. Now the position where the mount thinks it is pointing does not agree with the original stored position of the object. Pressing "Recal" updates the new position to equal the original co-ordinates. This is now a new reference point from which you can send the mount via GoTo and find other objects nearby with high accuracy.

Sync: when you loosen the clutches and move the mount manually to a known object or star, the mount has no information where you moved (there are no encoders on the axes). The only information that is in the mount's memory is the last position where it was pointed before you moved the mount manually. These co-ordinates might be off by 100 degrees! So, there is nothing in the mount to recalibrate on. Therefore you must tell the mount what the co-ordinates are where you are pointing. Example: you set up the mount and telescope for an evening of observing. There are no co-ordinates in the mount memory because this is a new setup. You loosen the clutches, and manually point the telescope at Sirius. Then you bring up Sirius in your keypad or planetarium program and "Sync" on the co-ordinates of Sirius. Now the mount has those co-ordinates in the memory and can find all other objects from that reference point with high accuracy.

The problem with using Sync happens if you point to a star with the counterweights higher than the scope. Then all subsequent slews will place the telescope below the mount. This can cause pier crashes.


-----Original Message-----
From: Vladimir Steblina <vsteblina@...>
Sent: Sun, Feb 7, 2021 12:23 pm
Subject: [ap-gto] Difference between Recalibrate and Sync

My friend and I have just about given up on the difference between Sync and Recalibrate with the AP900.

Can somehow explain the difference in terms we can understand?? 

What difference does it make??  When is it appropriate to use one versus the other??  Thanks.

Yep, we read the manual.  English is my fourth language and that is my excuse and I am sticking to it.....however, my friend is a native English speaker!!


Roland Christen

Join to automatically receive all group messages.