An Easy Workaround To Balance A Stiff Az-GTI

Many Sky-Watcher Az-GTI mounts suffer from a somehow stiff Az/RA rotation.

Usually, this is not a problem for tracking but makes balancing the payload a nightmare. If the motor does not stall during the rotation, though, there is no need to disassemble and fine-tune the mount.

But how to balance the payload then? Here is a quick and simple trick that does not require tools.

The idea is the following: fit the mount with all the gear you intend to use and balance it on a table in both RA and DEC. Some people balance the mount on the edge of a table, but that is far too risky for my taste and I prefer to have the mount sitting on something not too stable, like a small ⅜”-¼ adapter.

Here is the list of steps to follow:

  1. Pop your mount on a ⅜ - ¼ adapter with a large base, like these ones you can get off Amazon;

  2. Add your imaging equipment to the mount, together with the shaft and counterweight;

  3. Carefully, place the mount on a table, resting on the adapter, and move the counterweight so that the mount does not fall toward the payload or the counterweight;

  4. Slide back and forth the payload in the saddle so that the mount does not fall towards the front (lens/telescope heavy) nor backward (camera heavy);

  5. Gently bob the mount left/right, front/back, and “feel” how smoothly it comes to rest on the adapter to fine-tune the balance;

  6. Mark with a marker or a tape the position of the payload in the saddle and of the counterweight on the shaft;

Balancing the payload on a table.

Don’t go nuts with getting a precise balance: the whole procedure should not take you more than a minute or two to find a sweet spot for the balance. 

Also, mind that for RA it may be wise to leave the setup slightly unbalanced (east-heavy in the northern hemisphere) to help keep the gears under tension to reduce backlash.

If you use different setups having different weights, like me using a Samyang 135, a Sky-Watcher Evoguide 50ED, and a Celestron C5, you could use markers of different colors to mark the position of the counterweight on the shaft for each setup.

Here is a video I make about this.