Re: Crayford style focuser for Vario-Finder 10x60 ; 61x250 f/4.1

CurtisC <calypte@...>

Rolando has definite opinions about this.  As I understand it, the main scope is (usually) mounted in rings lined with felt.  As the scope moves, it moves around a tiny bit inside the felt lining.  But the guide scope, in the setup you describe, is mounted rigidly on top of the rings.  The main scope is moving within the rings.  The guide scope is not moving.  This introduces errors in the guiding.  The focuser itself, which is holding your camera, might move a bit.  The A-P bracket for the Baader mounts rigidly to the main casting of the imaging scope's focuser.  Now, in my case, using the Baader on my TEC140, I worry that the drawtube of the main scope's focuser may sag a bit as the main scope moves.  So the drawtube is moving, but the guide scope is not.  I haven't seen anything that I can definitely attribute to a sagging focuser drawtube.  But it's a worry.  

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