On Thu 2007-01-18T00:40:56 -0700, M. Warner Losh hath writ:
> "Thus UT1 is not, strictly speaking, a form of solar time"

This was the point made by Aoki et al. in 1982
when they replaced Newcomb's expressions (which had been based on
observations of the sun) with a new interpretation of what Newcomb had
actually done.  Then in 2000 Capitaine et al.
further removed the sun from the equation.  Despite being so openly
acknowledged in the literature this deviation from "solar" time eluded
even Jean Meeus until around 2005; look for a pointed example in his
next book on computational astronomy.

The current expression for UT1 will do well enough for civil time
until leap seconds would have to be happening every month.
One might wonder whether, in the light of modern measurements, Newcomb
would opine that his expression was supposed to be solar time.  The
slop of a full second in UTC made the original meaning of UT1 moot,
and the geophysicists took the advantage.

Steve Allen                 <[EMAIL PROTECTED]>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99858
University of California    Voice: +1 831 459 3046           Lng -122.06014
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m

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