Re: [LEAPSECS] name the equinox contest on now

From: Steve Allen <>
Date: Thu, 29 Jan 2004 13:27:02 -0800

On Thu 2004-01-29T16:20:10 -0500, Seeds, Glen hath writ:
> The problem I have is this: All variants of UT are supposed to be a close
> approximation of "the mean diurnal motion of the Sun". That makes perfect
> sense to me. Yet there is nothing in the statements above of how they are
> measured that seems to relate the earth to the *Sun*; rather, they all
> relate the earth to the [distant] *stars*. Can someone please explain how
> this can possibly work?

In short, it works for now. It won't work forever.

The interval between now and forever is sufficiently large that there
need be no rush to address the eventual disparity. UT1 will not
differ by more than one second from mean solar time until long after
we would need the first leap hour if we switch to atomic civil time.

I offer that I have covered this and given references to the critical
papers in the chain of definitions on my web page at

Steve Allen          UCO/Lick Observatory       Santa Cruz, CA 95064      Voice: +1 831 459 3046
PGP: 1024/E46978C5   F6 78 D1 10 62 94 8F 2E    49 89 0E FE 26 B4 14 93
Received on Thu Jan 29 2004 - 13:27:26 PST

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