[LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954

[Michael.Deckers]

On 2018-03-17 19:02, Steve Allen wrote:


> I am going to have to stop being amazed when I keep learning of yet
> another person taking credit for inventing the leap second.  The 1970
> IAU documents indicate that Winkler was one who warned that leap
> seconds would cause trouble for automated systems.  They also make it
> clear that there was not unanimity, and that there was overlap.


    [McCarthy 2009. p 228] states that leap seconds in UTC was an idea
    "introduced independently by Louis Essen and Gernot Winkler". It just
    was a variation of "Stepped Atomic Time" (SAT) that had gained some
    usage at the time, and was known to be practicable.

    Regardless of the amount of disagreement among astronomers then, there
    certainly seems to be some _current_ disagreement among astronomers 
about
    the future of UTC -- should leap seconds be omitted in the future so
    that UTC becomes a continuous time scale, or should we keep the current
    limit of |UT1 - UTC|?

    The current proposal [BIPM 2018. p 11..13, 32..33] for Resolution B 
of the
    General Conference of Weights and Measures 2018 makes UTC a time scale
    "produced by the BIPM" and recommends a revision of the limit |UT1 - 
UTC|.
    While the proposed Resolution does recommend work on improved 
dissemination
    of UT1 - UTC, it does not say anything about the dissemination of 
TAI - UTC.
    So, the likely future is that the limit on |UT1 - UTC| will be dropped,
    leap seconds will no longer be applied, and UTC will become a fixed
    translate of TAI (so that dissemination of TAI - UTC becomes 
unnecessary).

    Hence, people [astronomers?] interested in keeping the current 
definition
    of UTC should strive for improved dissemination of TAI - UTC, so as to
    make a continuous time scale easily accessible (for example, 
together with
    NTP time signals). The knowledge of current UTC, as a compromise between
    TAI and UT1, is, in the long term, obviously of less value than the 
knowledge
    of both UT1 and TAI together; the short term advantage of using UTC 
may only
    lie in the fact that it may be easier to newly disseminate TAI - UTC 
with UTC
    values than to extend the dissemniation of UTC to values of UT1 - UTC
    exceeding 1 s.

    [BIPM 2018] CGPM26 convocation: draft Resolution B
[https://www.bipm.org/utils/en/pdf/CGPM/Convocation-2018.pdf]

    [McCarthy 2009] Dennis D McCarthy, P Kenneth Seidelmann: "Time -- From
       Earth Rotation to Atomic Physics". Wiley-VCH Verlag. 2009 Weinheim.
       ISBN 978-3-527-40780-4.

    Michael Deckers.