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Hi Rex:
What you can see through an eyepiece and what you
can see on a negative shot at prime focus are amazingly different, at least for
me. Visually, an 800 mm scope with a 5 or even 10 mm eyepiece will give you very
obvious rings. Prime focus photography with the same 800 mm scope will give you
what Covington's equations show: about 0.2 mm for the entire planet-ring system.
With really fine grain film, you might be able to pull some detail out, but it
won't be easy. (BTW, for rough estimates, Saturn with rings is about equal in
diameter to Jupiter.) You should really go with eyepiece projection if your
prime scope is 800 mm. And don't forget the seeing factor---when doing visual,
your brain is rejecting the blurred periods of seeing and registering the
sharper moments. Film just captures what's there at the moment and usually it's
blurry (:-(( ).
Bert
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