On Wed 2014-11-05T11:11:38 +0000, Tony Finch hath writ: > Does anyone know where SOFA iauDat got its data for 1960 from? Because > that predates the USNO table.
I suspect they are the data from US NBS which Seidelmann included in the Explanatory Supplement. The numbers from BIH Bulletin Horaire during that year are consistent with some other references which say that UK NPL and US NBS did not get MSF and WWV aligned onto the new "coordinated" system until after the start of the year. My casual impression from Bulletin Horaire is that they got the transmissions lined up about a week into the year, and during that first year both sites just let their chronometers go with no attempt to resync. There are measurements of how far off were all the time scales starting from the inception of the BIH. I have a sampling of the numbers from 1960 in images here https://plus.google.com/photos/112320138481375234766/albums/6078225731350227361 The first few are a report on the initial effort to create an integrated atomic time scale. Note that those pages were published as much as a year after the dates of their data. The last few are from the year end summary for 1960. There are plots of how far each observatory deviated from Heure Definitive (which at that point had been and would continue to be UT2). There are offsets of each observatory during those months. There are measures of the offsets of each radio broadcast service during those months. The plots of deviations are kindof scary big, and I take them as powerful rationale that the IANA tz timezone project should make no effort to calculate sub-second offsets for far flung peoples. -- Steve Allen <s...@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs