Guider Scope-  Modified Orion/ Celestron 50mm finder scope

Modified guide scope is firmly clamped to the underside of the AP dovetail base......min. flexure issues!
Guide Scope-    Modification Steps

I used a 50mm finder scope from Orion
(same type as Celestron). Unscrewed rear eyepiece and used a piece of   frosted plastic to accurately, visually determine the focal point (~178mm) dimension.

I used my small bench-top lathe to removed the excess length of the tube

I then machined a 1-1/4 to 2" adapter to be shrunk-fit inside the ID of the 50mm tube.

Since my focal length dimension was fairly accurate, when I mounted the 1-1/4 nosepiece of the auto-guide camera, the objective lens only required a small focal adjustment.  Note: all dimensions needed to add up to the FL (depth to chip surface+ adapter space+ tube length.

Machined a custom clamp for mounting the scope

With the entire assembly clamp mounted, it was easy to adjust the objective lens and lock-it with the threaded lock-ring that these scopes use.

I have never touched it after running the focus routine in MaximDl and locking the setting down.
FIELD OF VIEW USING ORION SSAG:     2.1deg  x  1.7deg