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Old 22-01-2010, 09:52 PM
ericwbenson (Eric)
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Join Date: Sep 2009
Location: Adelaide, Australia
Posts: 209
Quote:
Originally Posted by gbeal View Post
Help me out here Trevor.
We are talking a 6" R/C with ~50% C/O, and a 4" apo, both with similar F ratios, correct?
You are saying the 6" is in no way comparable, how?
Gary
Ignoring Pi, 6*6 - 3*3 = 27 sq. in. versus 4*4 = 16 sq. in.
So the RC has 1.7 times more light grasp. About the same as going from a 3" refractor to a 4".

EB
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