[LEAPSECS] leap seconds schedule prior to 1972

Steve Allen sla at ucolick.org
Mon Apr 11 14:10:45 EDT 2016


On Mon 2016-04-11T10:17:33 -0400, John Sauter hath writ:
> Using ancient observations of the Sun and Moon, construct a time scale
> using the modern definition of Coordinated Universal Time to cover the
> past 3,000 years. Use the 20th century portion of that time scale to
> construct a table of leap seconds from 1900 through 1971 for NTP.

I find this to be akin to offering an answer to this question:
What is the arcsine of -2?

While there may be some applications which need that sort of answer,
in general it is important to recognize that prior to 1972-01-01 there
were no civil applications making use of SI seconds.  Every practical
application before 1955 was using mean solar seconds.

A time scale based on SI seconds extended back to 1900 does not
correspond to any contemporary use.  The nature of time scales in
actual use over history is necessarily piecewise continuous.
Applications should be aware of that and make a choice about whether
they want conceptual simplicity or a particular kind of technical
accuracy.  In general it is better for the characteristics of the time
scale to be driven by the needs of the application rather than
supplied in the absence of particular requirements.

So this is cool, and may be applicable to some applications, but I'm
not sure which ones those are.

--
Steve Allen                 <sla at ucolick.org>               WGS-84 (GPS)
UCO/Lick Observatory--ISB   Natural Sciences II, Room 165   Lat  +36.99855
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