Thread: f/5 vs f/4
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Old 10-08-2013, 08:24 PM
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Quote:
Originally Posted by Shiraz View Post
main difference is time. the f5 will take 25/16 times as long as an f4 to a given result, all else being equal. ...
Only for nebulae (extended objects)!
For stars, it will be the same.
Actually a bit worse... because the central obstruction (secondary) must be slightly wider for f4 system
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