[LEAPSECS] Inside GNSS published an update of my CGSIC talk

[Demetrios Matsakis]

Thank you Michael for pointing this out.   I’ve had InsideGNSS correct the on-line version.  I would be willing to bet that it will happen in 2035, but I am not privy to any inside information.

> On Mar 20, 2023, at 3:36 PM, Michael Deckers via LEAPSECS <leapsecs at leapsecond.com> wrote:
> 
> 
>    On 2023-03-20 07:54, Jürgen Appel via LEAPSECS wrote:
> 
> 
>> In your Conclusion, you say "the CGPM resolution also stipulates that no
>> change to current practices can occur before 2035."
>> 
>> This is not how I read read the CGPM document on the BIPM website:
>> "The General Conference on Weights and Measures (CGPM), at its 27th meeting
>> [...] decides that the maximum value for the difference (UT1-UTC) will be
>> increased in, or before, 2035,"
>> 
>> So in case the negative leap seconds become a real threat, according to my
>> interpretation is is an option to increase the tolerance value earlier than
>> 2035 to avoid trying out negative leap seconds a last and first time.
>> 
>> Can someone confirm my view?
> 
> 
> 
>     You read correctly, the French (official) version has
> 
>        ..."décide que la valeur maximale pour la différence
>            (UT1 - UTC) sera augmentée au plus tard en 2035,"....
> 
>     which means "in 2035 at the latest".
> 
>     Note also that the definition of UTC as approved by the
>     CGPM never mentions _any_ explict bound for |UT1 - UTC|; it
>     only says that (TAI - UTC) is an integral multiple of 1 s
>     as determined by the IERS. It is the IERS who state that
> 
>        "Coordinated Universal Time (UTC) a measure of time
>         that conforms, within approximately 1 s, to the mean
>         diurnal motion of the Sun and serves as the basis of
>         all civil timekeeping."
> 
>     quoting the IAU "Nomenclature for Fundamental Astronomy (NFA)"
>     found at http://syrte.obspm.fr/iauWGnfa/NFA Glossary.html.
> 
>     This seems to be lenient enough to allow for not scheduling
>     a negative leap second even in the case that the difference
>     (UT1 - UTC) should go a bit below -1 s before 2035.
> 
>     Michael Deckers.
> 
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