[LEAPSECS] the big artillery

Zefram zefram at fysh.org
Tue Nov 4 15:27:53 EST 2014


Brooks Harris wrote:
>                    To call it "UTC" seems a bit of a stretch to me,
>but there's no generally accepted name for what Zefram calls
>"rubber-seconds era of UTC". Everybody has seized the name, and
>attempted to give it some meaning other than what I, at least,
>consider to be its origin - 1972-01-01T00:00:00Z,

The name "Coordinated Universal Time" and initialism "UTC" are used
in the IAU 1967 resolutions, referring to the rubber-seconds system.
The resolutions note some possible tweaks to the tracking system.
For example:

    G. M. R. Winkler put forward a proposal to increase the tolerance
    of the representation of UT2 by UTC to 300 ms and to authorize the
    Director of the Bureau International de l'Heure (BIH) to change the
    frequency off-sets at the beginning of any month.
    ...
    D. Belocerkovskij confirmed that the coordination with the BIH in
    frequency will continue, but that the maximum tolerance in UT2-UTC
    is limited to 50 milliseconds.
    ...
    B. Guinot asked for statements by users on whether they prefer
    offsets in frequency or steps in time.

The name and initialism weren't used in the IAU 1964 or 1961 resolutions,
in places where one would expect them.  These resolutions refer to time
signals and the steering mechanism without ever naming the synthetic
time scale.

So the name was around before 1972 (though not as far back as 1961),
and did refer to the pre-1972 system.  I don't recall there ever being
controversy before on whether the rubber-seconds system is actually part
of UTC.  Those sources that use "UTC" to refer only to the leap-seconds
era do so merely out of ignorance.

-zefram


More information about the LEAPSECS mailing list