Re: [ATM] Clock drives and Tracking systems

[George Anderson <georgea@cam.org>]

Find an old mechanical rat, pick it up and turn it over. Rotate the ball
cover and have a look at the inside. Picture the two main shafts
extended to allow a drive motor on each one.
The main drawback is that you have no way of sensing slippage.
Now toss out the electronic sensors of the rat and use the drive you
just visualized. Place an optical rat directly underneath the ball and
use it to monitor ball rotation. Not the most accurate and you will need
to do some math for the outputs of the optical rat to be useful but it
should give you a starting point.

George Anderson
Montreal Canada

Clear skies and good health

artbianconi@blast.net wrote:
> 
> I love building mechanical systems and engineering them. However,
> What I know about the locations of heavenly bodies is limited to
> the local gym. Inspiring as some of the ladies are they do little
> to help me find M-33.
> 
> The current Ball & Socket design is an attempt to build a truly
> compact portable truss which has the ease of a "point and shoot"
> aiming of a Port-a-Ball, without the huge sphere.
> 
> It's not anything ground shaking as ideas go or at least should
> not be: it's simply a ball mounted solidly underneath the primary
> cell which is then fitted inside an adjustable clamp in much the
> same way your leg is fitted to your hip. I've tested it with
> temporary fixtures and it aims and stay put easily within any
> spot in given hemisphere. Presumably it will continue to do so
> after an OTA is fitted.
> 
> The problem is this: how does one aim it electronically with any
> degree of certainty? Worse yet, how does one aim it with any
> degree of repeatable precision?
> 
> Port-a-ball acknowledges that it's clock drive system is only
> accurate for a limited period which may eliminate it for serious
> astro-photography. Such accuracy is fine for a small aperture
> (6")  telescope whose primary design intent is portability and
> ease of use.
> 
> Because there is no surface for conventional optical readers to
> use, I must come up with another way of tracking. Anyone have any
> ideas?
> 
> Thanks
> 
> Art Bianconi
> 
> PS: if there's any interest in seeing the design, please e-mail
> me directly and I'll send some JPG's
> 
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