[LEAPSECS] the big artillery

[Zefram]

Michael Deckers via LEAPSECS wrote:
>  The symbol TAI(k) is defined in
>      RECOMMENDATION ITU-R TF.536-2: Time-scale notations
>  of 2003 with the text:
>
>  TAI(k): Time-scale realized by the institute "k" and defined
>          by the relation TAI(k) = UTC(k) + DTAI,

Oh cool, same as my definition.  I didn't know about this Recommendation.
I thought this notation was natural and intuitive, as a way of referring
to this concept, and it's nice to have that supported by an independent
coinage.  Also nice to now be able to refer to a definition with higher
status than "stuff wot I just thought up".

>  The contributions by the various metrology institutes to TAI
>  are independent from the UTC(k) and are denoted by TA(k) in
>  Circular T by the BIPM.

There aren't enough TA(k) to account for all the contributions to TAI.
The TA(k) are a small group, very rarely adding new ones, and notably
lacking some of the major contributors to TAI.  There's no TA(NPL),
for example.

-zefram