From: "Mel Bartels" 
To: 
Reply-To: "Mel Bartels" 


Yes, exactly my point that Kreige's book and similar Dobsonian designs are
meant for visual use.  Still, 17 arcminutes error from 3/4 inch rocker base
on 18 inch scope seems excessive to my experience.  Perhaps some
assumptions are unwarranted?

As far as pointing errors, I thought a long time ago about adopting
different Z1 Z2 Z3 values based on azimuth direction.  Easy enough in
software, but I never figured out a satisfactory strategy to analyze and
deduce what these values best should be.

This kind of stuff is very good and important because it illustrates that a
well mounted and well tuned telescope optimized for tracking and goto for
accessories involving long exposures takes a different strategy.

Mel Bartels

--- BBBS/NT v4.00 MP