GEM Balance problem?

JohnH · #1 21-09-2006, 10:32 AM

I have been told that for best results when guiding I should slightly offset the RA balance - this ensures the drive is always loaded and "lifting" the scope rather than braking it's fall...so I need to set up the balance differently either side of the meridian. My experiance seems to bear this out - with my scope "balanced" I track ok with the scope on the East side of the mount but get what looks like slippage with it in the West. An example is attached - can anyone confirm my diagnosis?

JohnH · #2 21-09-2006, 10:41 AM

In case you are wondering - my RA axis is quite stiff (the dealer does not want to slacken if off more) so it is quite hard for me to be sure of "perfect" balance...how much offset is healthy?

I need to put 250gm plus at the end of the counterbalance shaft to cause movement when the scope is static...

ving (David) · #3 21-09-2006, 11:08 AM

i do the same to make sure the ra is loaded... alas i cnt help you. my ra is pretty stiff too but i made it that way and i just adjust the weights untill it moves correctly onlong the axis.

[1ponders] (Paul) · #4 21-09-2006, 11:48 AM

I vaguely remember reading somewhere John that about 0.5kg/1lb is enough. I'll try to track it down. I tend towards the guestimate method. Mind you the RA and Dec axis on the losmandy G11 can be loosened right of to be freewheeling so its easy to judge when the east side is heavier.