"edz" wrote in message
om...
Here's what I did.

Photocopied the star image dot scale from my Sky Atlas 2000.0

Cut the copy with an exacto knife right down the center of the dots
that represent the different magnitudes. Measured the dots.

Stood in front of the mirror with my dot scale held up in front of my
eye (overlapping my pupil by one half) and slid the scale back and
forth until one of the half dots matched my pupil. I measured 5.5mmL
and 6mmR.

I was not able to do this in any light less than a subdued daylit room
light. In a fairly darkened room I could not see my pupils. In a
fully darkened room with a red light I could not see my pupils.
Turning even a low room light on I could see my pupils instantly
contract.

So last time (a few weeks ago) I visited the eye doctor I asked him to
measure my dark adapted pupils. He uses a similar half dot scale.
Only thing is he could not do it in a fully darkedned room. At first
in a fully dark room with a finger over his tiny light he got
7.5-8.0mm, but he stated he was having a hard time really seeing the
pupil accurately. He also needed to use a subdued light. With a dim
room light turned on behind me, he measured 6.5mmL and 7.0mmR.

My attempt at home was in a room far more lit that at the eye doctor's
office.

I'm near 51.

edz

http://astro.umsystem.edu/atm/ARCHIV.../msg00354.html


Dave