[LEAPSECS] LEAPSECS Digest, Vol 50, Issue 30

[Tom Van Baak]

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