ATM Fw: Hurst steppers and Dob Driver II

["Chris Westland" <westland@uxmail.ust.hk>]

----------
> From: Chris Westland <westland@uxmail.ust.hk>
> To: am@shore.net
> Subject: Hurst steppers and Dob Driver II
> Date: Thursday, September 05, 1996 6:48 AM
> 
> I have just purchased a Dob Driver II which I plan to use on a roller
type
> of drive system for my 18" Obsession style Dob.  I planned to let the
> weight of the scope sit on top of roller skate wheels (I think they are
> nylon).  This would mean throwing away some of the mounting hardware for
> the DDII ... in particular the belt and pulley system for the altitude
> bearing.  
> 
> Does anyone on this list have experience with the Dob Driver II, or the
> Hurst Stepper Motors that it uses?  What kind of drive rates do I need to
> consider.  I understand that the gearing on the motor shaft is 150:1, and
> that the motors are 10,000 step motors (after gearing).  But I think that
> the Dob Driver will adjust to a wide range of gearing ratios (I don't
know
> this for a fact) since it learns from the slewing that the operator
> performs to keep a star aligned.  So I am assuming that I only need to be
> in the "ball park" when computing the gearing ratios.   Does anyone know
> what is the dynamic range for this controller?
> 
> Thanks
> 
> -c
> 
> 
> 
> *********************************************************
> Chris Westland
> Hong Kong University of Science & Technology
> Clear Water Bay, Kowloon, HONG KONG
> Tel:                 ++852 2358 7643
> Fax:               ++852 2358 2421
> E-mail:          westland@uxmail.ust.hk
> WWW:           http://home.ust.hk/~westland/westland.htm
> *********************************************************
>