[LEAPSECS] A leap second proposal to consider -- LSEM

Steve Allen sla at ucolick.org
Thu Nov 4 16:59:36 EDT 2010

On Thu 2010-11-04T20:23:12 +0000, Michael Deckers hath writ:

> Yes, you are of course right. My point is that even UT1

> does not try. Sidereal time is no longer an affine

> function of UT1.

All forms of UT1 have been direct measures of earth rotation. One can
argue about zero points and drifts, but the underlying purpose of UT1
is to monitor rotation with a value that tracks where the sun is over
the earth. In that sense UT1 tries to be a form of mean solar time,
so it merits a name consistent with the 1884 IMC "universal day" and
the 1928 IAU "universal time".

This is not the case with a purely atomic time scale uncorrected for
the rotation of earth. To name that "universal time" is abuse.

Steve Allen <sla at ucolick.org> WGS-84 (GPS)
UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855
University of California Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m

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