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Balancing A Tandem Mount

Equatorial Mount Refractors
Multiscope Setup •6 replies•140 views
John Noble avatar
John Noble avatar
I’m trying to balance a tandem set up (side by side) with a 5” and 3” refractor. Can anyone share tips on balancing the DEC axis - I can’t seem to find anything out there so I’m guessing I’m searching for the wrong stuff! 3 D balancing seems to crop up a bit but I’m not sure what it is.

Perhaps I should have the scopes piggy back given the difference in length??

Thanks in advance for any pointers.

John
Engaging
Reg Pratt avatar
Reg Pratt avatar
Put your guide scope on the lighter of the 2 scopes and move your tandem bracket laterally until it balances.
Well Written Concise
John Noble avatar
John Noble avatar
Thanks Reg I can balance the scopes in any given position but the DEC goes out of balance as RA changes. So the whole thing balances perfectly home position but then goes increasingly out of balance in DEC while rotating in RA.

I’m guessing it’s because of the different scope lengths one is 900 mm the other is 540. Just can’t get my head around how to fix it but I’m sure someone out there knows how. Just for guidance there is a 10 to 15 pound difference between the two scopes.

John
Reg Pratt avatar
Reg Pratt avatar
Have you actually tested guiding performance yet? I wouldn't worry too much about things getting a little out of balance especially at that focal length and especially if you're within your mounts weight capability. Also if you're trying to keep the front of the lens hoods even with one another you may need to change that to achieve balance, I do. 

I've tried balancing my rig both parked and with the RA horizontal and have never had a problem with things getting a little out of balance as it moves. 

Supportive
fcbarclo avatar
fcbarclo avatar
I followed the procedure indicated in this link, obtaining very good results:
http://www.wilmslowastro.com/tips/g11gemini.htm#balancing

franco
John Noble avatar
John Noble avatar
Franco this is excellent thank you so much for posting - I had made the mistake of assuming if I balance each scope individually in the saddle the pair would be balanced. I'm off to try this now!!!

John

Took less than 15 mins to get this sorted - excellent result!
fcbarclo avatar
fcbarclo avatar
Im happy for you!

CS

franco