Re: [APML] Declination Drive problem

[steve banbury <banburys@sonic.net>]

Hi Bill--I'll bet someone else with more experience will step in with a good
suggestion, but perhaps there might some useful information for you on Mel
Bartels site. I'm thinking some of the motors he describes in his
applications could be used for yours.
Try a peek at: http://www.bbastrodesigns.com/cot/cot.html

Good luck--Steve

"William R. Mattil" wrote:

> Gentlemen,
>
> While probably Off-Topic I have a problem when guiding photographs that
> has me stumped. Situation is this, mount is a 1.5 inch shaft GEM with
> conventional RA drive and tangent-arm Dec driven by a Hurst 1 rpm motor.
> After being inspired by what I am seeing by lurking here I am trying to
> refine my guiding and have run into this. By definition I was told that
> tangent-arm Dec systems have "no backlash" and this seems plausable. But
> what I am experiencing seems to be just that. Backlash. When reversing
> directions there is a definent delay before the Dec reverses direction.
> After disassembling the Dec assembly and drive I have come to the
> conclusion that the "backlash" is present in the motor itself. Not the
> drive assembly itself. So I pondered this and cannot fathom a solution.
> I have three of these motors and they all exhibit the exact same
> behavior. I would imagine that constructing a new motor assembly would
> bear no fruit either since after adding the gears to reduce the speed to
> 1 rpm the backlash is introduced. That and the motor coasting. Can
> anyone point me in the right direction here ? I can guide in RA with
> *no* trouble at all, but this Dec thing is giving me fits.
>
> Perhaps superflouous information would be:
>
> 10" f/6 Newt. Guidescope is 90mm f/11 refractor. I am guiding at ~303x
> 9mm EP and 3X barlow. Flexure is *not* a problem.
>
> Trying desperately to get pin point stars .....
>
> Regards
>
> Bill
> --
> William R. Mattil       | Fred Astaire wasn't so great.
> wrmattil@ix.netcom.com  | Ginger had to do it all backwards
> (972) 399-4106          | and... in high heels.
>
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