Re: [LEAPSECS] Introduction of long term scheduling

From: Warner Losh <imp_at_BSDIMP.COM>
Date: Tue, 02 Jan 2007 12:27:01 -0700 (MST)

> Still, it's a strange assumption, given that TF.640 allows, I
> understand, leaps at the end of any month. Unofficially, the
> wording seems to be:
> > A positive or negative leap-second should be the last second
> > of a UTC month, but first preference should be given to the end
> > of December and June, and second preference to the end of March
> > and September.
> Anybody got access to a proper copy and can say whether that's
> right or not? If it is right then the Wikipedia article on leap
> seconds needs fixing.

The above is a direct quote from ITU-R-TF.460-4, annex I, section

Secont D.2.3 is the one that many people here would like to change in
some way, usually the time period:

"The IERS should decide upon and annoucne the introduction of a
leap-second, such an announcement to be made at least eight weeks in

Which many people would like see extended to a number of years. Heck,
a simple step would be to announce every 6 months the leap seconds for
a year, but I'll bet even that step would be politically difficult.

Curiously, BIH is currently, at least in the document I have, expected
to predict what the value of DUT1 is to .1 second at least a month in
advance so that frequency standard broadcasts can prepare for changes
of this value a month in advance. There's an exception for IERS to
step in two weeks in advance if the earth's rotation rate hickups.

Received on Tue Jan 02 2007 - 11:28:29 PST

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