Nah, the allen wrenches have blunt ends. :)
The method I have used is to wait until my eyes are dark adapted and while
looking at the sky to hold up the allen wrench vertically in front of my
eye. I increase the size until the allen wrench obscures the sky. This is
then my pupil size for when I am dark adapted. The only problem with this
method is that I don't own metric wrenches in 0.5mm increments, so I only
know to the closest mm.
-- Craig
> -----Original Message-----
> From: Richard Ozer [mailto:rozer@pacbell.net]
> Sent: Tuesday, July 27, 2004 2:01 PM
> To: tac@craigcolvin.com; The Astronomy Connection
> Subject: Re: [TAC] Exit Pupil size?
>
>
> Didn't that hurt?
>
> ----- Original Message -----
> From: "Craig Colvin" <tac@craigcolvin.com>
> To: <jvn@svpal.org>; "The Astronomy Connection" <sf-bay-tac@seds.org>
> Sent: Tuesday, July 27, 2004 2:52 PM
> Subject: Re: [TAC] Exit Pupil size?
>
>
> > I have done the same thing using metric allen wrenches.
> >
> > -Craig
> >
> >
> > ...... Original Message .......
> > On Tue, 27 Jul 2004 14:07:59 -0700 Jim Van Nuland <jvn@svpal.org> wrote:
> > >Mark Wagner wrote:
> > >>
> > >> Is there such thing as a pupilometer, so I can measure the
> > >> size of my exit pupil?
> > >
> > > I use a caliper. Point the scope & eyepiece at the daytime sky or
> > >lighted ceiling. Stand behind the eyepiece with both eyes open, about a
> > >foot or two back, and you'll see a tiny light disk, floating just above
> > >the eye lens. With a bit of practice, you'll find that you
> can hold the
> > >caliper at just the right distance. Adjust it in steps of 0.1
> mm or so,
> > >and you'll find that you can measure the image.
> > >
> > > OTOH -- if you know the actual focal lengths of primary and eyepiece,
> > >divide the eyepiece focal length by the f/ratio of the primary. Or
> > >divide the diameter of the primary by the magnification.
> > >
> > >
> > > OR -- did you mean to measure the pupil of your eyeball?? I'd call
> > >that your eye pupil, or entrance pupil, maybe.
> > >
> > > Cut a strip of paper about 300 mm long, tapered from about 12 mm wide
> > >to about 3 or 4 mm wide. Set up a small point source a few
> meters away.
> > >Put on your eye patch. Darken the room. Wait a while. Hold the paper
> > >strip vertically before your observing eye, and move it up and down
> > >until you *just* lose the point of light. It'll take some practice; as
> > >you move your head side to side, you'll see the light past each edge of
> > >the paper. What you want is to lose the light for the
> smallest instant;
> > >if the paper is too wide, you'll have a range over which the light is
> > >lost; too narrow and you won't lose it at all. When you believe you
> > >have the correct position, CAREFULLY mark the paper with a pencil, at
> > >your eye's pupil. Do it over a few times. At last, turn on your red
> > >light and see if the pencil marks are consistent. If so, measure the
> > >width at that spot.
> > >
> > > One of the secrets of a well-known SJAA comet hunter is that his
> > >dark-adapted eye has a 10 (ten) mm pupil!
> > >
> > >--
> > >Jim Van Nuland, San Jose (California) Astronomical Association
> > >JVN's home page
> > >
> >
Received on Tue Jul 27 15:52:46 2004