Patrick, Since you threw down the gauntlet (whether intentionally or not), I've spent the last couple of hours determining my pupil size. Didn't think I could sleep anyway. I recall that the last time I tried this test years ago I used a mirror because I was using a film camera and didn't have a cable release that was long enough to simply direct the camera at my face for a self portrait. Tonight (this morning) I used my Nikon D70 digital camera, and of course it was much easier. I set up the camera to take a direct image of my face while holding a scale by my eye. I waited ten minutes after turning out the lights then shot the picture. I measured a pupil diameter of just under7mm.
From the age of about 12 I've tried to wear sunglasses whenever I am outdoors and this protection seems to have helped give me fairly good night vision. I double-checked my notes and the first time I did this pupil diameter test I actually had an 8mm pupil diameter. Wikipedia gives a range of between 5mm and 9mm for pupil size in young adults (http://en.wikipedia.org/wiki/Exit_pupil) so I don't think that 7.2mm or even 8mm is necessarily on the high side for my age at the time. You can see, however, that my age appears to be catching up with me.
Kim -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Patrick Wiggins Sent: Wednesday, July 21, 2010 1:49 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] Measuring pupil size Ah, good idea. Maybe we could have a "pupil measuring session" during a star party at SPOC where instead of using a mirror we could go in the SPOC garage and have someone take pictures of those wishing to be measured. BTW, isn't 7.2mm a tad on the large size? patrick On 21 Jul 2010, at 01:37, Kim wrote:
I have used the following method to measure my pupil size: Set up a camera with a remote or cable release on a tripod in front of a mirror in a room that can be made completely dark. Focus the camera on your reflected image and prepare it to take a picture in the dark with the flash. (Beware not to use any redeye reduction pre-flash setting.) Turn out the lights and wait for your eyes to become completely dark adapted. Stand adjacent to the camera holding a subdivided millimeter scale next to your eye and take your picture. From the resulting image you can use the scale that you held by your eye to measure your fully dilated pupil size.
Last time I did this I measured my pupil to be about 7.2 mm in diameter.
Kim
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