[The_bluester (Paul)]

After a bit of possibly obscure knowledge!

Does anyone know what the maximum practicable field stop diameter is for an eyepiece before I will see vignetting turning up from the baffle tube or any other part of the light path?

I would be using a 2" visual back as the threads on the back of the scope support this, I have actually just got in the mail today my nice new SCT format 2" mirror diagonal.

The scope is a run of the mill CPC925 GPS with XLT coatings.