Re: ATM A Cage as Secondary Holder

[Al Kelly <akelly@ghg.net>]

At 10:05 PM 7/21/98 +0200, you wrote:
>
>I have to agree on this issue about stepper vibration being
>a bigger problem. In my work, I need very smoothe motion 
>for microinjection......<snip>...

I believe your requirements are much more demanding than even smooth
arc-second astronomical tracking accuracy, but it is certainly true that
even large, heavy telescopes may suffer from stepper vibration amplification
if stepper mounting is not cushioned or otherwise properly damped.  Chuck
Shaw has pointed this circumstance out to me on our Danciger 32" Newtonian,
which has an alt-az-fp drive.  We have successfully fought off the problem,
but it is a good example of the second-order issues that must be dealt with
once proper alignment of an unguided system is accomplished.

Al K.
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Al Kelly .... e-mail: akelly@ghg.net 
         .... web site: http://www.ghg.net/akelly/