Steve, See also "Time Scales" by Louis Essen for a whole set of interesting historical nuggets on the origin of UTC:
http://www.leapsecond.com/history/1968-Metrologia-v4-n4-Essen.pdf I would like to suggest that the rest of you read this as well. In case you didn't already know, it was Essen that made the first caesium clock. He was also the atomic time half of the 3 year experiment to measure and later define the SI second as 9 192 631 770 cycles... It's only a couple of pages long and while it's 30+ years old it highlights exactly the time scales issues being discussed here this week; the co-ordination of atomic clocks in labs around the world; the co-ordination of that atomic time scale with astronomical time scales; and the distribution of that time & frequency to the user. I like it for another reason -- it's the earliest paper I've found where leap seconds are mentioned; well not quite by that name -- instead it's "moving the minute marker along by 1 sec on a prearranged date, possibly 1 January and 1 June ...". What's interesting is that the metaphor is simply an analog clock (even precise timing equipment from that era was not digital). So in this paper at least the problems of :59:60 did not arise. /tvb _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
