Re: Stars in Stereo

[bercov@xxxxxxxxxxx (John Bercovitz)]

John R writes:

> I believe someone calculated a few years ago that the maximum 
> human stereo acuity would require a detection of difference in 
> spacings which is not too much different from the theoretical 
> resolution of an optical device with an aperture equal to the 
> human interocular.

That's an interesting statement.  I like it.  Let's see...  Were 
they talking the Rayleigh limit where something is just resolvable 
if the first minimum of one image spot (circular diffraction pattern) 
falls on the peak of an adjacent image spot?  That one is: resolution 
in seconds of arc = 114.5 mm divided by the diameter of the objective 
in millimeters for 555 nm light.  So following along with your argument, 
for 65 mm spacing of the eyes, the acuity would be 114.5/65  = 2" of 
arc which is in the same ball park as the very best stereo acuity 
(3" of arc)!  Amazing coincidence!  (Or I hope it is; this isn't the 
twilight zone, is it?)

John B


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