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platinum95yesterday at 9:03 AM1 replyview on HN

220 is a roll film, essentially the same as 120 film, just a longer roll. It's 6cm wide, and picture format depends on the camera/lens, varying from 6x4.5 up to 6x7 (and beyond, for panoramic shots).

So for use with your telescope, it'd need to produce an image circle that'd cover at least 6cm.


Replies

chantepierreyesterday at 9:32 AM

Thanks for the clarification. I don't think so, my largest eyepiece has a field stop of 39mm, and I'm taking advantage of the fact that edge illumination falloff is not perceptible in visual astronomy when the f/D ratio is low.