Thread: FOV and f ratio
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  #3  
Old October 2nd 04, 01:16 AM
Jon Isaacs
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Hi:

What kind of FOV can I get from an f 8.75 80mm refractor? What is the
relation that tells
you this?


1.25 inch focuser?

I believe the internal barrel diameter is around 28 mm for a 1.25 inch
eyepiece. This is the maximum field stop diameter which determines the maximum
possible Fielf of view.

The focal length of the scope in question is something like 8.75*80mm=700mm

The field of view will be 28mm/700mm = 0.04 radians x 57.3 deg/rad = 2.3
degrees.

2 inch focuser will be significantly greater..

jon