From: "Richard F.L.R. Snashall" 
To: ATM List 
Reply-To: "Richard F.L.R. Snashall" 


Up to now, I have been using the 2 inch eyepiece diameter as the field for
designing.  It never dawned on me to actually measure the diameter of one
!*(&*%

I have an old Edmund Scientific 32 mm ERFLE that has an ID at the focal
plane of about 42.7 mm.  (This seems suspiciously close to the 43.2 mm
diameter that R&V lists for 35 mm film.) Is this typical of 2 inch
eyepieces that I should be designing to that field diameter?  Or should I
actually design to something a little smaller so that the vignetting
softens the edge somewhat?

        Rick S.

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