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?!?