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. _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
