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To rebalance or not to rebalance...

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#1 Stargaz18

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Posted 25 February 2013 - 06:59 PM

I've never seen this question so thought I'd ask. Do you need to rebalance your scope when switching EP's? Some 2" EP's are close to 2 lbs in weight difference. And if you also add in a 2" barlow, even more. I never have rebalanced and I'm wondering if I need to. Thanks, Patrick

#2 David Castillo

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Posted 25 February 2013 - 08:59 PM

Yes! If I don't, my scope's servo drives groan in protest.
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#3 GOLGO13

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Posted 25 February 2013 - 09:20 PM

I think it's usually a good idea to do so. But it can depend on your scope setup. For instance, my 10 inch dob has a tension knob where I can just tighten the knob more and it will handle a heavier eyepiece. But, I could get some counterweights rather than tighten that up so much. I'd say if it's a really heavy payload I would do that (a 30mm Meade UWA for instance).

On my refractors I would rebalance if it were a significant change. You may have to anyways when you see your OTA start to move on it's own.

#4 JayinUT

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Posted 25 February 2013 - 09:33 PM

By drilling two new holes where the bearings attached I lowered my dob and moved the center of gravity. I attach a weight to the bottom and have a sliding weight on one of my strut poles and the scope stays balance throughout the night now.

#5 Madratter

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Posted 25 February 2013 - 10:25 PM

No I don't bother. I also have a CG-5. I balance at the start with my most commonly used eyepiece, which also happens to be middle of the road in terms of weight. As Uncle Rod says, the mount can sound like weasels with tuberculosis, but it moves around just fine.

#6 Tony Flanders

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Posted 26 February 2013 - 04:49 AM

If your scope is working OK, then you don't need to rebalance. If it's not working OK, then you do. Not surprisingly, the bigger the scope, the less it matters what eyepiece is in it. A 4.5-inch Dob is more likely to need rebalancing than a 16-inch Dob -- likewise a 5-inch SCT versus a 16-inch SCT.

Is your scope exhibiting symptoms that make you think rebalancing might be advisable?

#7 mich_al

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Posted 26 February 2013 - 07:59 AM

Someone (I think Televue) makes a weighted 1.25" to 2" adapter for this reason. In the past I have attached an appropriate weight to my diagonal using velcro. Normally I don't bother.

Al

#8 Ed D

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Posted 26 February 2013 - 09:30 AM

I drilled new holes to move the trunnions (pivots) on my tube Dob about an inch to balance the load with my binoviewer - talk about heavy! With single eyepieces it's a bit tail heavy, the opposite with the binoviewer. However, the normal spring tension between the base and trunnions is enough to hold the assembly in place.

In your case I suggest trying and playing with the eyepieces first before modding the scope. They may not have any significant impact on the balance.

Ed D

#9 Stargaz18

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Posted 26 February 2013 - 03:58 PM

No I haven't been having any problems Tony. I was just wondering if I needed to rebalance to avoid any future problems with the goto drive gears. Thanks for all your answers guys!






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