Re: leap second policy making (correction)

From: Rob Seaman <>
Date: Wed, 30 Aug 2000 10:29:18 -0700 (MST)

This mailing list has been so quiet that I actually reread one of my
own messages - and found this erroneous passage:

    Note that currently UTC is tied to the location of the prime
    meridian. One interpretation of a floating UTC is a floating
    prime meridian. We may be generating a vast market for surveyors
    in Great Britain over the next century as the meridian moves a
    couple of miles east of the Airy Transit Circle.
    (Or is it west? Quick! Which way?)

The estimate is that UTC will diverge from UT1 by about 140 seconds over
the next century. That's two minutes of time, but about 35 minutes of arc.
At the equator a minute of arc is a nautical mile. At the latitude of
Great Britain, 140 seconds of time is about 20 miles.

The final question remains, however. Which way does it move? If it's
hard for us to have complete confidence in sorting out this not entirely
pedagogical question in our own heads - should we be generating a
situation in which laypeople (bilyuns of 'em) would have to invert
the process in the future?

Rob Seaman
National Optical Astronomy Observatory
Received on Wed Aug 30 2000 - 10:32:45 PDT

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