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Rinaldo
Pooh-Bah


Reged: 06/28/04
Posts: 1245
Loc: Lawng-eye-lind - New York, USA
EQ Balance - 14lbs or 21lbs?
      #3168946 - 06/17/09 11:52 PM

I was wondering, is it better to use 14lbs further out on a counterweight shaft, or 21lbs slid higher up the shaft closer to the rotational axis? Or, does it not make any real difference?

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rdegoutier
super member


Reged: 02/18/08
Posts: 123
Loc: White Rock, BC, Canada
Re: EQ Balance - 14lbs or 21lbs? new [Re: Rinaldo]
      #3169011 - 06/18/09 01:01 AM

For an EQ6 I use 22 lbs (the supplied 2 x 11 lb weights).

To balance a MAK-Newt 190 it was not quite enough, so rather than packing an extra weight I added a 3 inch extension to the shaft (M12x3 bolt with a sleeve). It balances perfectly this way, but I have also tried 3x11 lb weights further up the shaft which also balances perfectly so either way should be OK as long as you can achieve balance. Personally I prefer not carrying and fooling with the extra weight.

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Sometimes I sits and thinks; sometimes I just sits.



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Chris Curran
scholastic sledgehammer


Reged: 06/14/05
Posts: 827
Loc: Brandon, FL
Re: EQ Balance - 14lbs or 21lbs? new [Re: rdegoutier]
      #3169341 - 06/18/09 09:26 AM

More weight closer in is always better than less weight farther out. On any GEM.

--------------------
cheers & beers,
Chris
Homepage | Over 40?



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rdegoutier
super member


Reged: 02/18/08
Posts: 123
Loc: White Rock, BC, Canada
Re: EQ Balance - 14lbs or 21lbs? new [Re: Chris Curran]
      #3170658 - 06/18/09 11:04 PM

Quote:

More weight closer in is always better than less weight farther out. On any GEM.




Yes, theoretically, The closer the counterweights are to the equatorial head, the greater the resonant frequency
and so the less problems with vibration, but I don't find that I have a vibration problem either way, and prefer to simply use the two supplied weights.

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Sometimes I sits and thinks; sometimes I just sits.



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Chris Curran
scholastic sledgehammer


Reged: 06/14/05
Posts: 827
Loc: Brandon, FL
Re: EQ Balance - 14lbs or 21lbs? new [Re: rdegoutier]
      #3170715 - 06/18/09 11:39 PM

It's not about resonant frequency... Think about it this way: put a 10lb sack on your back and hold 10lbs close to your chest to "balance" that pack. Count to 100. Now replace that 10 lbs and hold 2lbs out at arms length. Count to 100. You might make it, but I know I wouldn't.

Using less weight farther out on the cw shaft isn't going to hurt anything most of the time, but, if you're asking which is "better"...

--------------------
cheers & beers,
Chris
Homepage | Over 40?



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rdegoutier
super member


Reged: 02/18/08
Posts: 123
Loc: White Rock, BC, Canada
Re: EQ Balance - 14lbs or 21lbs? new [Re: Chris Curran]
      #3171512 - 06/19/09 12:51 PM

That's a good argument if your counterweight shaft is made of flesh and bone, but mine is a 3/4" steel shaft.
As long as you achieve static equilibrium, the result is the same. Basic physics, the Lever principle, Newtons Laws of Motion...
Sorry, I'm an engineer, which goes against my common sense not to argue.

--------------------
Sometimes I sits and thinks; sometimes I just sits.



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hudson_yak
Carpal Tunnel


Reged: 11/15/07
Posts: 1548
Loc: Hyde Park, NY, USA
Re: EQ Balance - 14lbs or 21lbs? new [Re: rdegoutier]
      #3171529 - 06/19/09 01:00 PM

Yup.

My impression with my SVP was that there was a bit more resonant jiggle with less weight located out at the very end, it was better with more weights further up, and with them spread out on the bar if using more than one weight.

Needs to be tried either way, certainly the less weight you can use the better for portability and so forth. The location of them may not matter if the mount itself is of stout-enough design.

Mike

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Tele Vue-85 + Quarter Hitch + Berlebach UNI 24
Meade 12" LightBridge
Orion ED100 + Losmandy GM-8
Orion SVP
Meade 8" LX10


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Chris Curran
scholastic sledgehammer


Reged: 06/14/05
Posts: 827
Loc: Brandon, FL
Re: EQ Balance - 14lbs or 21lbs? new [Re: rdegoutier]
      #3172358 - 06/19/09 10:16 PM

Quote:

Sorry, I'm an engineer, which goes against my common sense not to argue.




Me too! and ditto. Closer is better. No argument can be made to the contra.

--------------------
cheers & beers,
Chris
Homepage | Over 40?



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Zebra24601
Postmaster


Reged: 10/09/05
Posts: 16397
Loc: San Gabriel Valley, CA 91770
Re: EQ Balance - 14lbs or 21lbs? new [Re: Chris Curran]
      #3172628 - 06/20/09 02:20 AM

Well, except the extra 7 lbs you need to carry out to your set-up area!

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Zebra24601

Meade 8" SCT w/UHTC * Celestron 100ED * Celestron C11 * Celestron Firstscope 80EQ
Coronado 60mm Solar Max II * Meade LXD55 mount * Orion Sirius goto mount
Bushnell Voyager 4.5" Compact Reflector * Barska 15x70 binoculars * Galileoscope


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