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 -----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 12:26 AM To: utah astronomy utah astronomy listserve Subject: [Utah-astronomy] Measuring pupil size During last evening's SLAS meeting Prez. Dave covered basic telescope math including several mentions of various optical systems' exit pupils (basically diameter/power). During Advanced Training that followed I asked around about how to go about measuring the size of the eye's pupil. Dave and I both remembered the pupil measurement device Edmund used to sell but Dave noted it didn't do much good since it had to be used with the lights on. Anyone here have any ideas on how to measure pupil diameter under low-light conditions? Thanks, patrick p.s. As was noted in the meeting, Dave's talk was a historic first in that it was the first time he had ever given a presentation with a computer and *NO* slide projector. Could this possibly mean SLAS's aged and long suffering slide projector is now going to join the Mickey Mouse telescope in well deserved retirement?!? _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com