On Wed 2019-01-16T09:03:26+0000 Poul-Henning Kamp hath writ: > In message <20190116085619.ga23...@ucolick.org>, Steve Allen writes: > >The epoch of TAI, and LORAN, and GPS is 1961-01-01T20:00:00 UT2. > >Or maybe 1961-01-00 UT2. > > > >That is when the atomic time scale was set to a specified value. > > But the specific value they set was not zero in 1961-01-01T20:00:00 UT2, > they set it so it would have been zero at 1958-01-01 00:00:00 GMT
Because of the reset at 1961 (and other ingredients in the sausage of time) the difference between UT2 and TAI is not zero at 1958-01-01. It is close to zero, but it is not zero. One of the ingredients is that as of 1958-01-01 USNO was intentionally using a longitude that differed by 0.035 time seconds from the globally consistent value. I also have not read closely enough to say whether those offset values in the series H inception of A3 correspond to the values of UT2 before or after the longitudes of all stations changed on 1962-01-01. The global average for that shift was 1.5 ms. -- Steve Allen <s...@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 _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
