UTC - A Cautionary Tale Revisited

[Rob Seaman]

Howdy,

An entry for the "I hate it when I'm right" category:

On July 4th, the International Earth Rotation Service (IERS)  
announced that the first leap second in seven years will be issued at  
the end of December 2005.  This lengthy hiatus has been unprecedented  
- and the next paragraph may emphasize familiar warnings about idle  
hands.

On July 5th, the head of the IERS made the first quasi-official  
pronouncement that the next leap second may be the last leap second.   
The summary below is the most detailed proposal that has ever been  
circulated.  I've appended my slides from the VOEvent workshop for  
some context.  If you haven't visited Steve Allen's excellent UTC  
resources at http://www.ucolick.org/~sla/leapsecs, this would be a  
good time to do so and form your own opinions about the proper future  
for UTC.  There is some indication that Gambis himself supports the  
continuance of leap seconds.  If you agree, consider taking his  
advice and contacting the individuals indicated.

Time is short - literally.

Rob
------

Begin forwarded message:

> From: "services.iers at obspm.fr" <services.iers at obspm.fr>
> Date: July 5, 2005 4:48:40 AM MST
> To: adresc1 at callisto.obspm.fr
> Subject: Note to IERS Users
>
> July 2005
> Letter to IERS Bulletins C and D users
>
> Dear colleague,
>
> As you are probably aware, international discussions are in  
> progress on a
> redefinition of UTC, including a possible suppression of the leap  
> seconds
> procedure.
>
> To reply to the request of several international organizations on a  
> possible
> evolution of UTC the International Telecommunication Union, ITU  
> decided in
> October 2000 the creation of a Working  Group called "Special  
> Rapporteur Group",
> SRG chaired by Mr Ron Beard of the Naval Research Laboratory (NRL- 
> USA), in
> charge of studying by a large consultation the different possible  
> solutions.
> The SRG reports its conclusions to the ITU working party WP-7A.
>
> The Special Rapporteur Group (SRG) organized a colloquium in  
> Torino, Italy in
> May 2003. No general agreement emerged from this colloquium.
>
> In parallel, the US delegation to the WP-7A submitted, at the last  
> meeting in
> Geneva in October 2004, a proposal which contained the following  
> items:
>
> 1 - Maintenance of a time scale called UTC.
>
> 2 - Suppression of the leap seconds adjustments which maintains UTC  
> close to UT1,
> a time scale based on the Earth's rotation (currently UT1-UTC < .9 s)
>
> 3 - The difference of UT1 from UTC should not exceed 1 hour.
>
> 4 - The change should take effect at 21 December 2007, 00:00 UTC
>
> If your activity is affected by the content of the US proposal  
> which will be
> discussed in November 2005 at the WP-7A, you are urged to react.  
> This could be
> the last opportunity before a recommendation is issued by the WP-7A.
>
> If you wish you can express your opinion to your representative(s)  
> at the WP-7A
> of ITU (for the list see the ITU website, http://www.itu.int/home/ 
> index.html)
> with a copy to Daniel Gambis (daniel.gambis at obspm.fr), IERS EOP  
> Center.
>
> Daniel Gambis
> Head
> Earth Orientation Center of the IERS
> Observatoire de Paris



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