> I need an expert advise. I have an LX200 10 inches in
> equatorial mounting. I plan to buy a second hand Megrez 102mm
> to mount it in piggiback to the LX200 OTA. I dont know the exact
> weigth of this scope but it is something not negligible. I think
> I have to put a counterweigth on the opposite side of the OTA.
> However I see two different effects. On one hand I see that balancing
> the tube is beneficial for the telescope mechanisms to be less
> stressed, but on the other hand I also see that the installation
> of a counterwegth is adding more weigth to the total structure
> that the mechanics have to move. So I dont know what is better
> to decrease the total stress that the telescope has to suffer.
> My worry is about maximizing the mounting life duration. I dont
> like to damage the mechanics. Any advise would be appreciated.
Total mass, is less important than getting things balanced. You can
'minimise' the weight needed, by ensuring that the piggyback scope is as
close as possible to the main tube (this reduces the 'moment' it imposes).
Yes, you do want to balance, and you need what is normally called a '3D'
system. Ideally you have a weight below the tube that you can move in/out.
Aim the tube vertically, and adjust this for balance. Then aim the tube
horizontally, and adjust the position of the weight fore/aft along the tube,
till the scope again balances. Get this right, and the system will be
balanced at any point.
You should also lower the maximum slew rate you use. This is recommended
anyway, but the heavier the system, the more important it becomes, as it
reduces the work the motors have to do to accelerate/decelerate. The force
needed from the motors to accelerate to a particular rotation speed, depends
on the rotational inertia of the system, and this will rise with the extra
mass. Reducing this is the most important factor for drive 'life' when
dealing with a heavily loaded system.

Best Wishes

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