Luke Coletti wrote: > Define sunrise as the time when the apparent altitude (H) of the > upper limb of the Sun will be -50 arc minutes (34' for refraction + > 16' for semidiameter).
I thought this might give Bart a way out, but it goes in the wrong direction. If you define equinox the way any good witchdoctor would, as the date when day and night are equally long, or as the date when sunrise and sunset are 180 degrees apart, atmospheric refraction gives you a systematic discrepancy relative to astronomical data, shifting the equinox a good day farther into the winter. Unfortunately, Bart wants to get married a day farther into the summer. How about getting married in a valley, and counting the time the sun rises/sets over the mountain tops? Art -- To study, to finish, to publish. -- Benjamin Franklin Dr. Arthur Carlson Max Planck Institute for Plasma Physics Garching, Germany [EMAIL PROTECTED] http://www.rzg.mpg.de/~awc/home.html
