On 2018-02-05 08:11, Steve Allen wrote:
I have been diving through the library volumes with the contemporary
records of the early days of atomic chronometers. One of the things
that stands out is in this image
https://www.ucolick.org/~sla/temporary/tai1960.jpg
Great find!
...But I digress from this first publication of TAI. I have not seen any
historical synopsis that mentions this first use of a time scale with
the initials TAI. Has anyone seen a reference to this use?
If not, that begs the question of why not?
I have seen "temps atomique integré" in [Audoin 1998, p 53..55],
where the
authors explain it in detail, and say that it was used from 1960 until
1969-01-01 as a local atomic time scale at the BIH. Their point is that
comparisons of the readings of distant atomic clocks (first done via VLF
time signals) did provide good accuracy for the frequency but
insufficient
accuracy for the phase (even if done every so often). Hence the BIH was
forced to integrate (over a time scale apparently determined with quartz
clocks!) a mean value from atomic frequency observations to obtain a
consistent time scale with the rate determined by Markowitz et al. The
advent of LORAN-C reduced the uncertainty of long distance
comparisons to
the 1 µs level and the BIH then formed a mean reading of atomic clocks
(modern TAI, or, rather, EAL) -- as opposed to the integral of a mean of
the observed rates of these clocks (integrated atomic time). The name,
TAI, is used (proleptically) to denote both scales, and more, since
1955.
HTH
Michael Deckers.
[Audoin 1998] Claude Adoin, Bernard Guinot: "Les fondements de la mesure
du temps. Comment les fréquences atomiques règlent le monde".
Masson. 1998 Paris. ISBN 2-225-83261-7.
There seems to be an English translation for those who have not
perused scores of volumes of the BIH.
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