Re: Current manuals electronically?

Bill Long

Neutral balanced (rather than cw and camera side bias) improved the performance of the Mach 2 with the max capacity load on it that I've been running for this project. I assume the same will apply to the 1100, etc?

From: <> on behalf of Roland Christen via <chris1011@...>
Sent: Wednesday, August 4, 2021 8:26 AM
To: <>
Subject: Re: [ap-gto] Current manuals electronically?
You can do rough balance in both axes but then:

Always balance Dec first before final balance in RA.


-----Original Message-----
From: M Hambrick <mhambrick563@...>
Sent: Wed, Aug 4, 2021 10:12 am
Subject: Re: [ap-gto] Current manuals electronically?

Thanks for the heads-up Marj. I will wait for the new balancing recommendations.

In the meantime I have some questions about balancing that George, Howard, or Roland may want to comment on.

I have been taking advantage of the terrible weather here to check the balance of my imaging trains indoors. During this process I observed some behavior that has me concerned about whether my system is really balanced or not.

I followed the 9-step precision balancing procedure that is described in the current version (March, 2021) of the 1100 GTO manual:
  • Started from Park 3
  • Disengaged the RA gearbox and swung the CW shaft horizontal with the weights on the east side
  • Adjusted counterweights to achieve balance then slid bottom weight down slightly to bias weight very slightly towards the CW side.
  • Reengaged RA gearbox with CW shaft still in horizontal position.
  • Disengaged DEC gearbox and moved scope into horizontal orientation (facing south)
  • Moved scope in the dovetail to achieve balance, then slid slightly to camera end to bias weight slightly to the camera end.
  • Reengaged DEC gearbox
  • Repositioned the scope and mount into Park 3
After I completed this balancing procedure I disengaged the RA gearbox again with the mount in Park 3, and the scope immediately started rotating downwards. If I just let it go it would swung back and forth a few times and come to rest with the CW shaft approximately horizontal.

Next, I moved the mount into Park 2 and disengaged the RA gearbox again. This time the scope did not start swinging downwards, but behaved as it did during the RA balancing procedure with a slight bias toward the CW side.

The takeaway from this is that the RA balance is heavily dependent on the declination. My concern is how does this moving balance point affect the guiding performance.


Roland Christen

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