Thread: Fast & slow
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Old 29-01-2014, 07:42 PM
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mattyb217 (Matt)
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Join Date: May 2012
Location: Craigieburn, Vic
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Fast & slow

I was just wondering what the term fast or slow telescope was referring too. I read something the other day, it said a fast telescope has a focal ratio of f/5 or lower & a slow telescope has a focal ratio of f/6 or higher.
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