Re: [LEAPSECS] UT1 confidence

From: Poul-Henning Kamp <>
Date: Wed, 17 Jan 2007 12:49:25 +0000

In message <>, Zefram writes:
>IERS Bulletin A gives an expression for the uncertainty of its UT1-UTC
>data predictions:
> S t = 0.00025 (MJD-today)**0.75
>where "today" is the MJD of the bulletin's publication. The Bulletin
>only predicts a year ahead. Applying that formula gives an uncertainty
>a year ahead of 21 ms.

The question is what domain of validity the above formula has ?

In the builletin they only apply it up to 40d.

For an argument of 10 years the result is 0.12 seconds.
For an argument of 100 years the result is 0.66 seconds.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk_at_FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Received on Wed Jan 17 2007 - 04:59:46 PST

This archive was generated by hypermail 2.3.0 : Sat Sep 04 2010 - 09:44:55 PDT