Thread: Is a focal ratio on a 80mm APO refractor of f/6.9 too slow?
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Old 21-11-2018, 07:16 PM
Jethro777 (Jethro)
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Join Date: Oct 2012
Location: Brisbane
Posts: 131
Is a focal ratio on a 80mm APO refractor of f/6.9 too slow?
I intend to use it for Observation and down the track Astrophotography.
Specs are:

It's a APO 80 Triplet
80mm(3.15")
f550
6.9
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