SteveV Will I need 50mm filters to illuminate the guide chip without vignetting
Notice from the mechanical drawing that the guide sensor is almost at the edge of the M54 hole. I suspect that the guide sensor will get some vignetting even with a 2" filter.
You can print out their spec sheet on a piece of paper, and try to estimate more precisely. I suspect that the small sensor may be outside of your OTA's image circle, since the center of the main sensor is centered on the optical axis, and you will get the same problems that OAG users get (dim and distorted stars).
Chen
