On Fri 2010-09-03T17:45:34 +0100, Zefram hath writ: > I don't think an official realisation of GMT is required in order > for GMT to meaningfully exist.
That means it cannot be a precision time scale, for there is no authority to define a single realization. What the ITU-R is righly tasked to do is to specify a time scale to be used in broadcasts, and that does need to be a precision time scale, so that time scale needs a definition by an authority. > Does anyone have relevant historical documentation on the philosophical > definition of GMT? GMT is what time it was at the RGO meridian circle as interpolated from moment to moment by the best clock they had. It did not exist in any form prior to 1675. In response to the need to synchronize trans-oceanic telegraphy and as a result of a diplomatic coup hosted by the United States GMT became the basis for worldwide time. The extent to which local civil time needs to be a precision time scale is a different question, and the ITU-R has no direct authority over that. What we're going to see is whether the ITU-R points jurisdictions toward a greater understanding of the need to be careful about specifying time, or whether we are seeing another diplomatic coup in progress. -- Steve Allen <s...@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855 University of California 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