On Sun 2014-01-12T11:46:16 -0800, Brooks Harris hath writ: > So it appears the reference to the International Astronomical Union (13th > General Assembly, Prague, 1967) is where the recommendations from > BIH come to the statement in > > l.A.2. Recommendations of the 5th Session > of the Consultative Committee for the > Definition of the Second > > RECOMMENDATION S 4 (1970) > > 4. The origin of International Atomic Time is > defined in conformance with the recommendations > of the International Astronomical Union (13th > General Assembly, Prague, 1967) that is, this scale > was in approximate agreement with 0 hours UT2 > January 1, 1958. > > So the 1958 origin was made *official* by this Recommendation. Is > that your understanding?
I am not sure what "official" means in the context of recommendations by one body which can be ignored by another body. It is a statement by the CCDS produced under direction of the CIPM which is an extreme shorthand for saying that they believed that the atomic time scale being maintained by the BIH was based on that 1959 agreement that everyone would reset their atomic time scales to epoch 1958-01-01, and that the CCDS believed the BIH had done an adequate job at that task, and the CCDS wanted the next-step-farther-removed-from-the-technical-details delegates of the CIPM to communicate the same thing up to the next-step-up... delegates of the 14th CGPM so that they would officially approve the inception and ongoing maintenance of TAI. In this case the recommendation happens to agree with what IAU comms 4 and 31 had said in resolutions 4 and 5 on page 182 at http://adsabs.harvard.edu/abs/1968IAUTB..13..178S so everybody was happy. But in the same 1967 IAU GA were also resolutions 1 and 2 by comms 4 and 31 (in that same document, but note that there are typos in the enumeration and pagination) which were considered important enough that the entire GA approved them as resolutions 5 and 6 seen on page 41 at http://adsabs.harvard.edu/abs/1968IAUTB..13...41. and the CGPM utterly ignored resolution 5b, so not everyone was happy. I find that the last point at which everyone was in agreement about what the meaning of things were was the 1964 IAU GA discussion in http://adsabs.harvard.edu/abs/1966IAUTB..12..304M which was written by none less than astronomer W. Markowitz, radio-timekeeper H.M. Smith, and physicist L. Essen which was included in the resolutions (see page 16) http://www.iau.org/static/resolutions/IAU1964_French.pdf By the time of the 1967 IAU meeting the statements by various folks who reported the situation in the CCIR and the BIPM seemed to be using imprecise paraphrases of what had been recorded in the proceedings of those other agencies. The documents from the different agencies use different terminology when describing what they must have meant to be the same thing. That left room for paper consensus without actual agreement on the mechanisms. Up until 1970 all of the CCIR recommendations about radio broadcast time scales were basically descriptions of the existing best practices. Recommendation 460 became prescriptive of a change which had not been implemented by anyone, and its prescription contained no instructions about the details of accomplishing the change. The CCIR working party rushed to come up with in interim implementation document before the 1972 deadline. During the next decade the CCIR rejoiced as they saw 460 get adopted by the IAU, the CGPM, the WARC, the CCITT, the governments of France and Germany. Nobody seems to have stopped to ask just how exactly those leap seconds were supposed to be communicated nor handled by systems that could not interpret a telegram from the BIH. -- 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 http://six.pairlist.net/mailman/listinfo/leapsecs