[LEAPSECS] Civil timekeeping before 1 January 1972

[Steve Allen]

On Tue 2015-05-05T15:32:30 -0700, Paul Hirose hath writ:
> The rubber time era can be tricky. I just finished a major rewrite
> of my UTC implementation in the C# language. The goal was improved
> accuracy before 1972. Although the old version passed all my tests
> at 1 microsecond accuracy, it began failing when I tightened the
> error tolerance to 1 nanosecond.

And it should fail, and you should not be concerned.

I am looking at the BIH Circular D63 from the end of 1971/beginning of
1972 which tabulated the time from laboratories around the world (that
particular issue being the one that saw the transition from rubber
seconds to SI seconds).

The tabulations of the times of emission of radio broadcasts of UTC
were given in units of, and with an accuracy of 0.0001 s; i.e., 100
microseconds.

The tabulations of the intercomparisons between the time scales in
those laboratories are given with decimals to 0.1 microsecond, or 100
nanoseconds.

> I don't believe 3 ns is significant for any time stamp from that
> era.

Right.  There is no record of the available time scales that can
say anything about the time differences at that level.

--
Steve Allen                 <sla at ucolick.org>               WGS-84 (GPS)
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