[time-nuts] 15 Seconds error...??

Mike S mikes at flatsurface.com
Wed Jan 18 19:04:49 EST 2012

On 1/18/2012 6:15 PM, mike cook wrote:
> I'm not sure anyone says "don't" use TAI. What they say is that you
> "can't" use TAI because it is not disseminated , unlike UTC(k).
> UTC has the same rate as TAI , so we have a source of Si ticks, but TAI
> is not on the wire.

But there's the rub. Many people/organizations use "UTC," and it's 
enshrined in many legal systems. But, just like TAI, is really only on 
paper as it isn't known until after the fact, when all the contributing 
clocks are compared and the data massaged.

Are the after-the-fact published offsets between, say, UTC(USNO) and TAI 
and UTC different? (except for the integer TAI/UTC difference)? I guess 
I'm assuming that TAI is published as after-the-fact offsets from clocks 
which are disseminated, which means UTC(k), no?

Put another way, can someone say they know UTC any better than they know 

US Code says "Coordinated Universal Time defined
In this section, the term “Coordinated Universal Time” means the time 
scale maintained through the General Conference of Weights and Measures 
and interpreted or modified for the United States by the Secretary of 
Commerce in coordination with the Secretary of the Navy."

You tell me, is that UTC, or UTC(USNO) or UTC(NIST), or something 
completely different?

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