Re: [Utah-astronomy] Pupil envy

You can sure save a bunch on eyepieces too. No point in getting a short F/L 2" eyepiece since most of the light won't make it through the pupil.

A diminishing pupil diameter with age is the trend, although by no means does it happen to absolutely everyone- thus the need for the gauge.

If it helps, Rich, think of it this way: The older you get, the more efficient your eyes get, so the fewer photons you need to achieve the same level of sensitivity... ;o)