Subject: Re: bug#16663: emacs/calc/date

From: Steve Allen <[email-masked]>
Date: Thu, 6 Feb 2014 21:45:27 -0800

On Thu 2014-02-06T23:28:26 -0600, Jay Belanger hath writ:
> > For dates prior to atomic chronometers UT is defined more precisely
> > than the sources of time that were available to most users of civil
> > time.
>
> Which doesn't tell me what UT is.

For most practical purposes UT is GMT.

> > Piles of details about all these time scales are here
> > http://www.ucolick.org/~sla/leapsecs/timescales.html
>
> For those that want piles of details; I suppose.  I was wondering which
> version of UT you were referring to.

The different forms of UT coincidentally happened to be defined during
the same meeting which announced the results from the first cesium
atomic chronometer.
Before cesium atomic there was just UT.
After cesium atomic there was UT0, UT1, UT2, but it hardly matters.
Until about 1972 there were fingers-on-hands-countably-few sites with
chronometers capable of noting the difference between flavors of UT.

--
Steve Allen                 <[email-masked]>                WGS-84 (GPS)
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