[time-nuts] What time is it anyway?

Magnus Danielson magnus at rubidium.dyndns.org
Sun Mar 28 11:36:26 UTC 2010


Chris Cheney wrote:
>> I think that is the BIPM (http://www.bipm.org/en/home/) in association
>> with the IERS (http://hpiers.obspm.fr/)
>>
>> Peter
>>
>>
>> On 28 March 2010 10:29, Steve Rooke <sar10538 at gmail.com> wrote:
>>     
>>> What puzzles me is who is the keeper of "legal time" for the other
>>> 93.4% of land mass and 95.5% of population of the World other than the
>>> US.
>>>       
>
> _By definition_ (ITU-R-TF.460-4, Annex 1), the keeper of UTC is BIPM with 
> assistance from the IERS. But "legal time", being a national matter, is 
> something quite different and might or might not be aligned with UTC, 
> depending on the individual nation state.
ITU gets its authority from being an UN organisation. The reason they 
have TF.460-4 is because there are radio transmitters for time. Nowadays 
that document should be handled differently than ITU-R.

BIPM gets its authority from the signature nations of the metric 
convention, which then meet in the General Conference on Weights and 
Measures (CGPM) and International Committee for Weigths and Measures.

http://www.bipm.org/en/convention/
http://www.bipm.org/en/convention/cgpm/
http://www.bipm.org/en/committees/cipm/
http://www.bipm.org/en/convention/member_states/

In addition to all that, there is a number of related organisations for 
related calibration, traceability and accreditations. ISO is also a part 
of the mixture.

Just go to BIPM and the above links and read for yourselves. With a 
little curiosity you will eventually figure out how everything connects.

It all boils down to nations signing a number of binding agreements. 
That creates a common reference system, mutual recognition, same 
procedures etc.

Cheers,
Magnus



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