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