Re: ATM Mel's System

[akelly@ghg.net (Albert F. Kelly)]

At 10:06 AM 5/28/97 -0700, you wrote:
>>
>This may work on Mels system, but will not on a system that uses full or 
>half steps.  Stepper motors index very quickly and in my experience will 
>slip if there is not a gear reduction between the motor and the friction 
>drive.  
>

No question about it.  At the same time, if one does the necessary gear
reduction, as Andy Saulietis has done in his exquisite design, the friction
drive system works wonderfully well.  Both Andy and Mel have found ways to
make unguided CCD imaging with large, fast alt-az systems a new wave in the
ATM/CCD world.  Chuck Shaw and I have become primary beneficiaries and our
testimonies will undoubtedly increase as time goes by.  

I invite list members to look at recent images I have posted on my website  
( http://www.ghg.net/akelly/ ) to verify the unguided tracking and image
plane derotation capabilities of Andy's design.  My 17.5" f4.5 Newt has been
converted to the Saulietis Alt-Az-FP system and we are converting the 32" f4
Newt now.

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