[ATM] [atm_free] RE: Focal Ratio for a Fast 24"
mbartels at bbastrodesigns.com
Tue Mar 15 10:56:15 JST 2011
eyes. I'm turning 50 this year and if I interpret your chart properly I'm
already in the 5.5 mm range so I would lose light at a 6mm exit pupil. Do
you know if the chart assumes complete dark adaption or normal skies for
astronomy? Perhaps there is not difference.
Every person is different. You should measure your exit pupil. At age 50 I
wouldn't be surprised that your exit pupil is 6+mm. One should always been
dark adapted while observing, regardless of sky conditions <smile>!
I'll appreciate guidance during final figuring to make sure I meet the
extremely tight tolerances of an f/3.3 figure. I'll l have to think more
Other than a star test which other testing methods were you referring to?
Best to not start with a new foreign test during making of a f/3 mirror.
However, adding a test or two to your arsenal is always a good idea. I like
the indoor star test - very discerning.
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