NavList:

Alex, you wrote earlier:

"However there are well documented cases of much higher resolution.
(One person tested in XIX century had resolution of 1",
but this seems to be the world record. Several people were described
who could see the phases of Venus with naked eye)."

 

I mentioned before that I was skeptical, and it only dawned on me while I was throwing out last week's back-of-the-envelope calculations that one arc-second resolution is literally impossible. The diffraction limit is imposed by the laws of physics and gives a lower limit of 15 arcseconds under the very best of circumstances (under typical circumstances, this optical limit is about 30"). If Nature chose to pack more cone cells into our foveas than one for every 15" of angle across the retina, they would not yield higher resolution.

 

Can anyone think of a loophole I've missed here? The diffraction limit has some fuzziness of definition (there's a pun in there somewhere), but I don't think it's enough to help.