From: "Mel Bartels" 
To: 
Reply-To: "Mel Bartels" 


>>>
    I guess my question goes to more of a quantum level.  WHY is it possible
to see such small detail?  Doesn't current wave theory of light say that
ANY point of light, whether from a star or a point on a planet or in a
nebula, create a diffraction pattern of an Airy disc and rings upon passage
through even a perfect telescope?
<<<

With all due respect, you are going about this backwards.  Start with the
eye-brain, its characteristics, how it detects images, and once that is
(dimly because the eye-brain's processing is complicated) understood, then
lay out what optical system it takes to deliver that image.

By fixating on the Airy disk you are making unwarranted assumptions.  For
instance, treating the eye as some sort of impartial digital detector with
no further image processing, and, confusing resolution with detection, and,
confusing image analysis (detecting a line thinner than Airy disk).  Don't
forget that in the real world, aperture much over 8 inches rarely sees much
of a true Airy disk anyhow, and the actual star is a complicated blur or
scintillation of the Airy disk over time.

In the case of Cassini's Division, ask yourself what does it take for the
eye to see a thin black line on a bright background.  Once you get that,
determine what optical system can meet the standard.  That analysis I would
very much like to see .

Mel Bartels

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