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GEM balancing
Hi,
If you are doing imaging or want to use the telescope manually without locking the RA and DEC all the time you need to balance the tube on 3 axes which means it is dynamically balanced all the time.
I think Sidgwick has diagrams.
You need to balance the OTA and balance weights when the RA is horizontal, and the tube on the 3 axes. It takes a bit of working out to get the tube in 3 orthogonal orientations. You probably need to go round a few times because of adding weights as you go. One is vertical and the other two are horizontal with the tube rotated 90 degrees.
On my old Fullerscopes MK4 mount I had as large diameter knobs made for the RA and DEC clutches so I could finely set the loading so I could manually move the scope and have the motor continue driving afterwards.
Then it is usuall to set it slightly out of balance if motorised so the scope is resting slightly on the gears to reduce any backlash.
If the mount is well greased up that tends to help with damping.
If the OTA is well within the mounts capability then it is easier to get it set so that it is easy to use.
Cheers. Andrew.
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