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unable to get a even balance

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#1 supertrucker

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Posted 25 May 2019 - 01:32 AM

 hello, i'm new to the hobby and just started to learn my new equipment after several attempts i am unable to get anywhere near a perfect balance just when i think i have it balanced rotate the R A  or the same situation in the DEC just when i think it appears balanced it's not. i have a orion siruis pro az eq-g mount and a orion 150mm maksutov a 9 x 50 illuminated RA finder scope a 2" diagonal a dew shield that weighs about 1/2 pound and the polar alignment scope that mounts on to the left side of the mount. i think the finder scope may be the issue it sits kinda high and heavy also the polar align scope is on same side on the mount. my final balance is close but i'm not sure if this can damage the goto motors gears belts ect-.


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#2 Gary Z

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Posted 25 May 2019 - 01:57 AM

Why do you think it isn't balanced?    Sounds like you're setup for visual, and if you are very close, it should not be a problem.  Your polar alignment scope should not factor in your balancing.  Only your scope, your accessories attached to it and your counterweights for balancing out.   

 

To alleviate any confusion over what you are doing, it might be a good idea get some pictures of how you have things on your mount.  You can then upload to your gallery or save the images to the cloud and link to your images there.  

 

Gary



#3 supertrucker

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Posted 25 May 2019 - 02:27 AM

okay next time i have it set up i will take some pic's and post them 



#4 supertrucker

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Posted 25 May 2019 - 03:28 AM

scope (2)_edited.jpg this does not show how the finde scope sits to the left of center on the optical tube 



#5 NMBob

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Posted 25 May 2019 - 09:41 AM

Well, it's not put together upside down or anything. :) 

 

If you loosen all the clutches what will it do in the picture? The whole mount will rotate (the RA axis) so the telescope tube (OTA) is toward the wall or toward us, or does just the telescope tube spin around (the Dec axis) so it is pointing toward the floor, instead of the sky? Make sure you have everything attached that you are going to use to observe when balancing. Just changing eyepieces can make it necessary to rebalance. You just have to shoot for the average. You can go through all of the combinations and make notes/put little marks on things to identify where counterweights and the telescope tube should be for different setups.

 

It could be the combination of the finder and polar scope on the same side if it is the OTA that's spinning. If a car tire is heavy on one side you have to add a weight on the opposite side fix the balance. My Lunt solar scope has a big lump of brass on one side (the pressure tuner) and I have to take that into account when balancing. I add a second telescope. :)

 

Mount the polar scope on the near side? I see two little screws there.



#6 Phil Sherman

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Posted 25 May 2019 - 09:49 AM

When the finder scope is mounted left of center, this moves the center of mass of the scope plus finder away from the mount's axis. You'll never get a perfect balance with this arrangement because, as the mount rotates, the center of mass of the load changes position relative to the mount's axis. There's a number of possible solutions.

 

You could install a second mount for the finder, located on top of the scope, opposite the VIxen rail on the bottom.

 

You could attach some lead fishing weights to the scope on the opposite side from the finder to bring the center of mass back along the mount's axis.

 

Another alternative would be to modify one of the counterweights with a shaft that sticks out to one side. A small counterweight on the shaft will allow you to balance out the offset weight of the finder. Unfortunately, you might have issues with the additional offset weight on the counterweight causing it to rotate on its shaft. If this becomes an issue, a second locking screw could also be added to the counterweight.


Edited by Phil Sherman, 25 May 2019 - 09:50 AM.

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#7 emflocater

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Posted 25 May 2019 - 10:11 AM

I had a similar issue caused by the finderscope. I decided to use a smaller much lighter type finderscope and that helped very much. Was not perfect but darn close enough and much better than before. Only other thought as someone else mentioned, is to move your finderscope directly centered on top of your SCT, but not sure how well that goes when you look through the finderscope if your head gets in the way of anything such as your focuser or eyepiece or main tube etc. 

Cheers

Don



#8 skaiser

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Posted 25 May 2019 - 10:49 AM

As I understand setups, you normally set your scope to be somewhat unbalanced on purpose.

that way it helps minimize backlash issues in the drive train.

if you are viewing to one side of meridian, then you like to have your scope slightly heavy to the opposite side.



#9 Hesiod

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Posted 25 May 2019 - 11:20 AM

You have goto, so the finderscope is basically useless (especially a large one); my suggestion is to ditch it and get a small red dot finder for the initial calibration.



#10 supertrucker

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Posted 25 May 2019 - 11:34 AM

it balances just fine without the finder scope, so either i go with a much lighter finder or attach / strap on weights opposite of finder. i believe i will go with a lighter finder any suggestions ? 



#11 supertrucker

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Posted 25 May 2019 - 11:39 AM

okay the red dot finders sounds like the way to go.thanks.



#12 Chuckwagon

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Posted 25 May 2019 - 11:40 AM

Are you having tracking issues?  If not, ignore the imbalance.  It isn't that severe.  Most mounts don't require perfect balance.  Especially if you are doing visual work.  So unless you are having a problem, ignore it.



#13 supertrucker

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Posted 25 May 2019 - 03:48 PM

tracking issues  not really noticeable. i did not follow the advice given earlier about using a right angle finder as a primary finder it makes spotting more difficult. i think what hesoid said about going with a red dot finder sounds more practical and will take care of the balance issue and drop some weight off the top also.




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