Load balancing of the 10Micron GM mounts

[DanH]

Hi all GM users,

I've read that the 10Micron mounts have a useful tool to aid in balancing the load. That is indeed very nice !

Until now, using my old CGEM, I was always slightly un-balancing the mount to have it a little bit heavier on the EAST site (I'm in the northern hemisphere).

This guaranteed that the wheel would be pushing the load to the WEST, instead of having the OTA "fall" to the WEST.

How does the 10Micron mount handle this ? Is it supposed to be perfectly balanced, or does the tool take that slight un-balancing into account ?

Dan

[perfrej]

It is supposed to be totally balanced, simple as that. It is important apparantley, mostly because of the high slew rates. The older firmware showed balance to 1/100th of a percent, while the newer just displays 1/10th of a percent. Balance is considered OK when the figure is below 0.2%.

The routine is simple; just go into the drive menu, select balancing, then "Balance Ra". You should have it roughly balanced as a prerequisite. There is also a setting that enables the use of set slew rate between balance positions, and without it it will use the same speed for the slew as for the measurement, making it a slow process. I use 10°/s slew normally so balancing is fast. The scope will slew to a position at roughly Az/Alt 0/10 and move back and forth slowly (like 3°/s) twice, then move to the other side of the medridian and repeat. It then reports scope heavy or shaft heavy and the percentage. Adjust and press enter and the process is repeated. I'll shoot a videao of it in the near future

Same thing for Dec apart from the fact that it is more cumbersome to move the scope up and down. If you park the mount via my mountsend utility when you adjust the OTA, the hand controller will remain in the balance menu and you can iterate with a simple push of the enter button. If you park via the menues you will have to re-enter the balance menu and that takes much more of your valuable play time!

/per

[DanH]

Thank you Per !

As I say quite often : "It's better to find one that knows, than ten that are searching"

[Tim]

The mounts are so sensitive to balancing that when I fitted a new focuser to my SCT and moved the mirror right back in the cell, the scope was very apparently heavy on one side. When I focused it again, balance was restored!

[perfrej]

Yep, the measurements from the motors are pretty accurate, that's for sure. I have run my GM2000HPS quite unbalanced by a few kg and it worked fine under those conditions too, but of course it should be properly balanced. I do not know any figures for backlash but the both the GM1000 and the GM2000 fel very solid and free from slack.

/per