[LEAPSECS] happy anniversary pips
sla at ucolick.org
Thu Feb 6 10:19:47 EST 2014
On Thu 2014-02-06T11:32:09 +0000, Ian Batten hath writ:
> All the coverage again points out that the "Greenwich" time signal is in fact a melange of
> UTC(GPS), UTC(NPL) and the BBC's own atomic clocks, rather than GMT (ie UT1).
> Another indicator that although UK legal time is UT1, in practice not only
> does everyone use UTC, but sources of UT1 with better than 100ms resolution
> are difficult to access in real time (MSF only carries DUT1 to 100ms).
I still have those PDF scans of the 1984 letter from Martine Feissel
of the BIH which show the slow demise of the entire ensemble of
instruments which had once played the earth rotation game along with
Greenwich. I need to extract the plots as jpeg files for easier
embedding into web pages as examples when discussing this issue.t By
the time those plots showed no more data input from optical transits
there wasn't any tie left to the original GMT.
On the subject of leap seconds in the UTC time scale I think there has
been only one publicly identifiable commercial voice (someone correct
me if I've missed others):
Google and the leap smear.
Taken at face value Google's Site Reliability Team would seem to be
arguing for the return to the bad old days of the rubber second.
It's hard to believe that Google's Android and driverless car divisions
hold the same position, but they haven't spoken.
Many ITU-R actions are in response to draft proposals which have been
sent through the process by commercial entities. Their voices reflect
their business needs. The process of coming through the working parties
sometimes obfuscates who wants the new draft, but the small number of
players in the telecom fields makes that hard.
In this case it's as if there are no commercial voices at all who wish
to be seen as contributing to the revision of TF.460. That is strange
and unusual. This nebulous lack of clear technical voice is the
atmosphere in which the RA was asked to vote 2 years ago, and it's
little wonder that they decided not to decide.
Steve Allen <sla at 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
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