[ATM] [atm_free] RE: Focal Ratio for a Fast 24"

[Mel Bartels]

>>>
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
about f/3.0... 
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.

 

Mel Bartels