On Mon 2020-05-04T19:58:42-0600 Paul Gilmartin via tz hath writ:
On 2020-05-04, at 18:26:22, Andrew Gierth wrote:
(To the best of my knowledge there are no reference clocks available to which one could synchronize in order to use a mean solar time, so your argument seems to me to support this choice.)
Do you mean mean solar time at some arbitrary precise longitude or mean solar time at the Prime Meridian? If the latter, is interpolated UT1 a close enough approximation?: https://www.nist.gov/pml/time-and-frequency-division/time-services/ut1-ntp-t...
UT1 is not mean solar time, but it is the quantity which is conventionally recognized as mean solar time. In 1954 Sadler recognized that by its existing convention UT (not then yet named UT1) deviates from mean solar time. https://www.ucolick.org/~sla/leapsecs/Sadler1954.pdf Seago and Seidelmann explored this much more deeply in 2013 https://www.agi.com/resources/white-papers/the-mean-solar-time-origin-of-uni... and showed how an alternative formulation might be developed if calendar days are to continue be determined by measuring rotation of the earth. -- Steve Allen <sla@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m