On Sun, 17 Apr 2022 at 08:37, Dennis Lee Bieber <wlfr...@ix.netcom.com> wrote: > And proposals to make > DST permanent year round -- so "noon" (1200hrs) is not "noon" (sun at > zenith) pretty much anywhere. >
Noon isn't precisely zenith anyway, for several reasons: 1) Time zones synchronize their clocks on the mean noon at some location. Usually that's approximately close to the most populous part of the region, but not always - for instance, all of China is on one timezone, despite spanning 4-5 hours' worth of solar noon. 2) Solar noon migrates around a bit during the year. I don't remember the exact figures, but if you want to read a sundial with any precision, you need to take a date-based adjustment. 3) Solar days aren't all 24 hours long anyway. The clock and calendar should *roughly* correspond to the sun, in that broadly speaking, 2AM will be in darkness and 2PM will be in sunlight, and the solstices will land in June and December. But down to the minute, it's much more useful to synchronize on atomic time than astronomical. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
