Jump to content


Photo

EQ Balance - 14lbs or 21lbs?

  • Please log in to reply
8 replies to this topic

#1 Rinaldo

Rinaldo

    Apollo

  • -----
  • Posts: 1405
  • Joined: 28 Jun 2004
  • Loc: Lawng-eye-lind - New York, USA

Posted 17 June 2009 - 10:52 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?

#2 rdegoutier

rdegoutier

    Vostok 1

  • -----
  • Posts: 123
  • Joined: 18 Feb 2008
  • Loc: White Rock, BC, Canada

Posted 18 June 2009 - 12:01 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.

#3 Chris Curran

Chris Curran

    Viking 1

  • *****
  • Posts: 827
  • Joined: 14 Jun 2005
  • Loc: Brandon, FL

Posted 18 June 2009 - 08:26 AM

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

#4 rdegoutier

rdegoutier

    Vostok 1

  • -----
  • Posts: 123
  • Joined: 18 Feb 2008
  • Loc: White Rock, BC, Canada

Posted 18 June 2009 - 10:04 PM

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.

#5 Chris Curran

Chris Curran

    Viking 1

  • *****
  • Posts: 827
  • Joined: 14 Jun 2005
  • Loc: Brandon, FL

Posted 18 June 2009 - 10:39 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"...

#6 rdegoutier

rdegoutier

    Vostok 1

  • -----
  • Posts: 123
  • Joined: 18 Feb 2008
  • Loc: White Rock, BC, Canada

Posted 19 June 2009 - 11:51 AM

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

#7 hudson_yak

hudson_yak

    Surveyor 1

  • -----
  • Posts: 1573
  • Joined: 15 Nov 2007
  • Loc: Hyde Park, NY, USA

Posted 19 June 2009 - 12:00 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

#8 Chris Curran

Chris Curran

    Viking 1

  • *****
  • Posts: 827
  • Joined: 14 Jun 2005
  • Loc: Brandon, FL

Posted 19 June 2009 - 09:16 PM

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


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

#9 Zebra24601

Zebra24601

    Hubble

  • *****
  • Posts: 16430
  • Joined: 09 Oct 2005
  • Loc: San Gabriel Valley, CA 91770

Posted 20 June 2009 - 01:20 AM

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






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics