All Members of list: Please forgive an elision in a message I mailed today, a little over an hour ago.
In the passage on using a sextant as a "sundial." I wrote: " .... (Note that depending on the size of the eye-piece aperture and distance of the eye behind it,, you can easily get resolution limitation due to diffraction image size increase at reduced effective 1/F number, and so not have the nominal eye's 1 minute of arc best-resolution when observing contact of the arcuate limb with a visible horizon. .... )" This should have read: " .... (Note that depending on the size of the eye-piece aperture and distance of the eye behind it,, you can easily get resolution limitation due to diffraction image size increase at reduced effective relative aperture, ( higher 1/F number,) and so not have the nominal eye's 1 minute of arc best-resolution when observing contact of the arcuate limb with a visible horizon. .... )" Please forgive this and other past, and I'm sure also future to come, such lapses you may find in my messages. Bill Maddux
