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Re: Cat's eyes



People!

Many cats are nocturnal, esp. house cats.

bc

P.s. Some students (and I, at UCSC, Physics) use(d) this property of the eye to illuminate the cross hairs when aligning the spectroscopes that don't have the internal 45 deg. glass plate in the eye piece.

John Denker wrote:

At 10:03 AM 9/6/00 -0400, Ludwik Kowalski wrote:
>The size of the spot was more or less
>the same as the size of the iris.

Not surprising.  I assume you mean "pupil" not "iris".

>The glowing eyes of the cat were as large as the entire
>exposed parts of eyeballs.

Not surprising.  Implies experiment was done when the cat was dark-adapted.

>Do cats have irises ?

Sure.

For a moderately light-adapted cat, see e.g.
   http://www.andrew.cmu.edu/user/mckinney/closeupCat.jpg

Almost everything you see is either pupil or movable iris -- as opposed to
immovable sclera.  When fully dark adapted, all the green (iris) will be
retracted.  A fully dark-adapted cat has a huge numerical aperture.

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