OTA Counterweights needed?

[gregbradley]

http://www.astro-physics.com/index.h...ducts/products

I am wondering why there is a counter weight on the top of this AP RHA.

Does it improve balance somehow? Any thoughts?

Greg.

[AndrewJ]

Gday Greg

I reckon its there to replace a guide scope that isnt currently fitted at present.
Ie i reckon they balanced the unit for a main scope and guide scope, then removed the guide scope and used the upper weights to rebalance.
That way they can mixn match without ever having to move the main counterweights.

Andrew

[gregbradley]

Thanks Andrew.

That may be the case. I was wondering if its best practice to put a counter weight up top to help centre the gravity of the scope as many scopes are top heavy.

Like where you balance the scope horizontally but its out of balance at the angle you image at.

Greg.

[AndrewJ]

Gday Greg

I was wondering if its best practice to put a counter weight up top to help centre the gravity of the scope as many scopes are top heavy.

Nope.
The static balance point of the system is relative to the RA and DEC axles of the mount, not the fitted scope .
If you add a weight where they did, you will always need to compensate on the other side of the RA axle, ie the std counterweights.
I can see no logical reason to stick a weight where they did unless it was to simulate something else that may be fitted there.

Andrew

[gregbradley]

Thanks for that Andrew. I oftened wondered about that.

Greg.