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Old 14-01-2010, 08:11 PM
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Geoff45 (Geoff)
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Focal ratio myths

Are the following assertions true or false?
  • The smaller the f number, the shorter the exposure you can use.
  • A 10" f8 scope is slower than a 6" f4 ie needs longer exposures
  • Aperture is more important than focal ratio
Interesting reads here
http://www.stanmooreastro.com/SamplingFratioMyth.htm
http://www.stark-labs.com/blog/files/FratioAperture.php

Geoff
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Old 15-01-2010, 12:42 AM
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deadsimple (Ash)
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The second link was especially interesting, thanks for posting.
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