[LEAPSECS] future access to solar time?

[Seaman, Robert Lewis - (rseaman)]

Hi Tony,

The time zone system and daylight-saving time are layered on UTC. My clock shows Mountain Standard Time year-round. Other people’s show other local times and 10-15% of these change by an hour twice a year. These small complications will not be made simpler by attempting to remove the concept of mean solar time from the system. Those who want to dispute this might ask themselves why they bother, considering the lab-coated acolytes of atomic time have already voted to redefine UTC.

Similarly, complications like the equation of time and its graphical representation as the analemma don’t change the (current) fundamental traceability back to mean solar time. See innumerable discussions on this list or at meetings like Exton or Charlottesville. We are ultimately not talking about the “leap second” we are talking about the definition of the word “day”.

Many astronomical systems do care at the level of the current UTC approximation. Some care at much higher precision. So, what alternative standards and infrastructure will be available in the future?

Time to move on…

Rob


On 11/20/22, 10:31 AM, "LEAPSECS" wrote:

External Email

Seaman, Robert Lewis - (rseaman) <rseaman at arizona.edu> wrote:
>
> Getting the solar time currently means looking at your watch or the
> upper right-hand corner of the monitor.

Well, no, not for more than half the year. I happen to be close to the
Greenwich meridian so my clocks currently show something close to mean
solar time (about 30 seconds fast, I think?) but that isn't true for most
people.

I assumed from your complaint about losing access to solar time that you
cared about roughly-second or subsecond precision, because if your
precision requirements are "look at the clock on the wall" your complaint
does not make sense. The clock on the wall tells the time for social
purposes, not for the position of the sun in the sky.

--
Tony Finch  <dot at dotat.at>  https://dotat.at/
Isle of Man: West 5 or 6, backing south 3 or 4, then southeast 6 or 7
later. Mainly moderate, becoming slight for a time. Showers, rain
later. Mainly good, becoming moderate or poor later.
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