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Re: Cat's eyes



At 19:02 9/3/00 -0400, you wrote:
P.S.
It is very unlikely that our cat will be cooperative tonight.

Then perhaps a cat's eye surrogate would be better.

After thinking about yesterday's observations it occurred
to me that one fact is not consistent with the lens-mirror
model of John's.

My daughter was on the left side of me, actually in my
shadow, as far as the kitchen fixture is concerned. Yes,
she was still illuminated by the scattered light but not
as much as I was. And yet we observed the glowing
eyes at the same time.

Perhaps the eyes were glowing, but not as much from her
viewpoint. How would you know?

More significant was the fact that she was about 3 feet
on my left side. The distance to the cat, from each of
us, was about 15 feet. The eyes of the cat's could not
possibly be directed simultaneously at me and at her.
The lens-mirror retroreflection is supposed to be in
the direction of the lens axis (cat's eyes), not in
several directions at the same time (as it would be
if the eyes were mirrors arranged in the corner
cube configuration).

This idea that retroreflexion is confined to the optical axis
seems to have been introduced by Ludwik.
It will help to mention that the photosensitive surface of the
mammalian eye is not planar.

Would we still see the glowing (not flickering)
cat's eyes at the same time if the distance between
us were much larger that three feet?

I imagine so. My field of view appears to exceed 70 degrees.
A seperation of three feet at fifteen feet range is about
0.2 radians

A dark face
mask and simultaneous observations of the glow
by two people are important factors, as far the
validation of the explanation is concerned.
Ludwik Kowalski


brian whatcott <inet@intellisys.net> Altus OK
Eureka!