[LEAPSECS] future access to solar time?

[Seaman, Robert Lewis - (rseaman)]

Interesting!

Another example of “polysemy” (http://hanksville.org/futureofutc/aas223/presentations/2-1-ISOterminologyAAS.pdf) in timekeeping.

In addition to changes in funding (be careful what you ask for, precision time community), best practices (and worse practices) should get a good workout as this foundational standard is redefined.

Rob



On 11/21/22, 8:30 AM, "LEAPSECS" wrote:

    On 2022-11-21 14:19, Seaman, Robert Lewis - (rseaman) wrote:

> In a post-leap-second world, precision values for dUT1 either become more critical or less. Or rather, they become no-less important scientifically but perhaps negligible politically. For example,https://www.sciencedirect.com/science/article/pii/S0273117719302388  says “Global Navigation Satellite Systems (GNSS) are dependent on VLBI as they need dUT1 to maintain its operability”.



    I am not sure if we mean the same thing by "dUT1". I used
    it in the sense:
       dUT1 is an additonal correction to UTC so that
           UTC +  DUT1 + dUT1
       is a better approximation of UT1 than just
           UTC +  DUT1
       and takes its values in the set {0, ±20, ±40, ±60, ±80} ms.

    dUT1 in this sense is used only by some Russian time signals,
    and its value is not defined by the IERS. Moreover, since the
    amplitude of UT1 - UT2 is about 34 ms, dUT1 must be adjusted
    for annual variations of UT1 - UTC.

    I have seen the term "dUT1" to be used for ΔUT1 = UT1 - UTC
    (and that is how I read it in the paper you quoted), and
    also for the rate d(UT1) -- but these are different beasts.

    Michael Deckers.

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