Subject: Re: Comment on draft FITS standard revision 1.2 (fwd)

From: Patrick Wallace <ptw at star.rl.ac.uk>
Date: Wed, 22 Apr 1998 15:47:50 +0100 (BST)

Steve Allen <sla at ucolick.borg> writes:

> 5.4.2.2
>
> This is something I wish I'd caught during the wordsmithing of the Y2K
> text.  The intent of the phrase
> "shall be UTC for dates since 1972 and UT before" is perfectly
> clear to someone who understands that the UTC epoch began
> 1972-01-01.

Not so:  UTC started in 1960.  See Trans. IAU Reports, XIA, 362-364 or,
more accessibly, the table in

   ftp://maia.usno.navy.mil/ser7/tai-utc.dat

1972 is when they stopped using rate adjustments and introduced leap
seconds instead.

Patrick Wallace
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Starlink Project Manager                        Internet:  ptw at star.rl.ac.uk
Rutherford Appleton Laboratory                       Tel:    +44-1235-445372
Chilton, Didcot, Oxon OX11 0QX, UK                   Fax:    +44-1235-446667
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