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#1 StrangeDejavu

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Posted 22 November 2013 - 04:31 PM

Sorry for the broad title, I didn't know how else to word it.

My CG-4 has two counterweights, 8 lb and 4 lb. I recently acquired an 8" SCT which is right at 12 lbs by itself. When dealing with counterweights, is it best to match the weight you have mounted, or is it okay to have more? For example, Celestron only sells 11 lb counterweights for the CG-4 and CG-5. The 11 lb plus my 4 lb would put me at 15 lbs. The SCT with finder and camera ready will likely be 13.5 lbs. Will this cause problems?

#2 Falcon-

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Posted 22 November 2013 - 04:55 PM

The counterweights do not need to exactly match the weight - that is why the counterweight bar is so long. By adjusting the position of the weight in and out you can make the total leverage balance out. So if your counterweights a bit lighter the scope they just need to be farther out on the bar, if the counterweights are a bit heavier they just need to be slightly closer to the mount on the bar.

There is only a problem if there is a large mismatch between counterweights and scope. Even then something like a counterweight shaft extension can sometimes solve the problem without adding more counterweights.

#3 StrangeDejavu

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Posted 22 November 2013 - 05:17 PM

Thanks Sean, I didn't know this. :) Since I have 12 lbs, I should be able to just keep the weight at the very bottom then and be good to go.

#4 Falcon-

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Posted 22 November 2013 - 05:23 PM

Actually that is probably too much to be all the way out at the end of the counterweight bar. One way to find the correct balance would be something like this:

- Set up mount on the tripod
- attach counterweights near end of the bar
- attach the telescope and accessories
- release the RA clutch to check balance (keep a hand on the scope JUST IN CASE). You will almost certainly need to move the counterweights up the bar (towards the mount) to get a good balance. When properly balanced and the clutch released the scope can be moved with a light touch of a finger!

You also want to have at least a reasonable balance in DEC - to do that you need to shift the scope's position in the dovetail clamp. Gota be careful doing that though of course as you do not want the scope to slip off the mount while adjusting it!






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