On 2015-02-05 05:53 PM, Kevin Birth wrote:
If one can read Japanese (which I can do with great difficulty and veeerrrry
slowly), one notes that the official Japanese announcement refers to the IERS
and the leap second policy, but it translates UTC 23:59:60 on June 30 into the
local time of 8:59:60 on July 1. So Japan follows the policy, but the policy
does result in next leap second occurring on the morning of July 1 locally.
But there's no *specified* standard, I think, right? Warner points out
it "I believe it follows trivially from the definition of timezones.".
I'm not so sure it "follows trivially", especially that there's no
*official* specification for "time zones" either, as far I can tell. The
"offset from UTC" is referenced in ISO 8601 but only provides for
representing that offset, not defining its meaning.
The “International Meridian Conference” (more properly, the "The
International Conference Held at Washington for the Purpose of Fixing a
Prime Meridian and a Universal Day. October, 1884") did NOT adopt the
resolution to establish a “date line” or “time zones”. The following
proposal was defeated:
"The Conference recommends as initial point for the universal hour and
the cosmic day the mean mid-day of Greenwich, coinciding with the moment
of midnight or the beginning of the civil day at the meridian 12 hours
or 180 degrees from Greenwich. The universal hours are to be counted
from 0 up to 24 hours."
That proposal was “lost”, in the words used at that conference, and no
official proclamation of these facts has since been proposed or
approved. Nonetheless, the idea of “beginning of the civil day at the
meridian 12 hours or 180° from Greenwich” has found its way to common
use, but also (unofficially) extended to +13:00 and +14:00.
Many aspects of "local time" or "civil time" are left to "common
practice" which is not good enough to expect uniform inter-operable
implementations. We here concentrate on discussions of UTC and Leap
Seconds, which is foundational, yet obviously "local time" is required
and there's nearly a complete lack of standards that govern it. Fixing
Leap Seconds, either by more clearly defining it so implementations can
get it right (my very strong preference) or ceasing Leap Seconds (which
some hope will mitigate the problems but I believe will make it worse)
doesn't address the elephant in the room - local time.
-Brooks
Cheers,
Kevin
________________________________________
From: LEAPSECS [leapsecs-boun...@leapsecond.com] on behalf of Warner Losh
[i...@bsdimp.com]
Sent: Thursday, February 05, 2015 5:36 PM
To: stephensc...@videotron.ca; Leap Second Discussion List
Subject: Re: [LEAPSECS] final report of the UK leap seconds dialog
The leap second happens world wide in UTC at 23:59:60. Since all time zones
follow UTC,
it is whatever time that is offset from UTC. Otherwise, the offset would no
longer be fixed,
but variable for a few hours. While there isn’t a standard for this, I believe
it follows trivially
from the definition of timezones.
I’ve never seen any jurisdiction that’s done it differently ever. That’s just
the sort of thing that
people would bring up arguing against leap seconds because it would be insanely
stupid to
do this.
I’m also pretty sure that a local time zone isn’t a local time scale in the
strictest sense of
time scale. Again, I don’t have a reference to site for this.
Warner
On Feb 5, 2015, at 2:37 PM, Stephen Scott <stephensc...@videotron.ca> wrote:
Hello Kevin.
The information specifying that for Japan the next Leap Second will be applied
Wednesday, July 1, at 9:00. is interesting in that this is the first official
policy on when the Leap second shall be applied to a local timescale. Maybe I
have been looking in teh wrong places.
This is a local decision for a local time.
I am not aware of any international standards that touch the subject.
I would be interested in learning about other jurisdictions that may have
published a policy.
Stephen Scott
On 2015-02-05 09:35, Kevin Birth wrote:
Wednesday, July 1, at 9:00.
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