Re: [LEAPSECS] USNO press release

2016-07-11 Thread Brooks Harris 

Slight tweaks were suggested offline ...

The International Earth Rotation and Reference Systems Service (IERS) 
has determined that a positive Leap Second shall be introduced in the 
Coordinated Universal Time (UTC) timescale at the end of the day on 
2016-December-31. The positive Leap Second will be inserted immediately 
following the second labeled 23:59:59 and it will be labeled 23:59:60. 
Most world clocks will introduce this positive Leap Second on their 
local timescales simultaneously with its occurrence in UTC. The U.S. 
Naval Observatory's Master Clock Facility in Washington, DC will insert 
this positive Leap Second in the Eastern Standard Time (UTC-05:00) 
timescale on 2016-December-31 immediately following the second labeled 
06:59:59 pm (18:59:59) and it will be labeled 06:59:60 pm (18:59:60).


-Brooks

On 2016-07-11 09:45 AM, Brooks Harris wrote:
"WASHINGTON, DC -- On December 31, 2016, a "leap second" will be added 
to the world's
clocks at 23 hours, 59 minutes and 59 seconds Coordinated Universal 
Time (UTC). This
corresponds to 6:59:59 pm Eastern Standard Time, when the extra second 
will be inserted at the

U.S. Naval Observatory's Master Clock Facility in Washington, DC. "

It seems to me not exactly wrong, but misleading in several respects:

1) Its a *positive* Leap Second
2) "introduced" or "inserted" rather than "added" are better terms 
consistent with ITU-R 460.
3) The Leap Second is not, typically, "added to the worlds clocks" in 
the same way its introduced to UTC. If "world clocks" means "local 
time" the Leap Second will typically be introduced on the local 
timescales simultaneous with its occurrence on UTC.
4) "added .. at 23 hours, 59 minutes and 59 seconds" might be 
misinterpreted to mean *before*, or somehow together with, 23:59:59. 
"Inserted following" might be more clear.

5) there's no mention of what happens in the other USA time zones.

Its always a challenge to write about UTC in a way that's both clear 
and readable. Here's my go:


The International Earth Rotation and Reference Systems Service (IERS) 
has determined a positive Leap Second shall be introduced in the 
Coordinated Universal Time (UTC) timescale at the end of the day on 
2016-December-31. The positive Leap Second will be inserted 
immediately following the second labeled 23:59:59 and labeled 
23:59:60. Most world clocks will introduce this positive Leap Second 
on their local timescales simultaneous with its occurrence in UTC. The 
U.S. Naval Observatory's Master Clock Facility in Washington, DC will 
insert this positive Leap Second to the Eastern Standard Time 
(UTC-05:00) timescale on 2016-December-31 immediately following the 
second labeled 06:59:59 pm (18:59:59) and will be labeled 06:59:60 pm 
(18:59:60).


-Brooks

On 2016-07-10 11:26 PM, Jonathan E. Hardis wrote:
I don't disagree with your interpretation of UTC, but there's no 
error in the announcement.  The leap second is */added/* */at 
/*23:59:59.  While the leap second itself is 23:59:60, it's during 
the interval 23:59:59 when the logic is changed for what the next 
second should be labelled.


 - Jonathan


On Jul 10, 2016, at 3:39 PM, Paul Hirose > wrote:


On 2016-07-08 12:16, I wrote:

Is there a mistake in this announcement?


http://www.usno.navy.mil/USNO/tours-events/2016_Leap_Second%20Press%20Release%20-%20Final.pdf


WASHINGTON, DC -- On December 31, 2016, a "leap second" will be 
added to

the world's clocks at 23 hours, 59 minutes and 59 seconds Coordinated
Universal Time (UTC).


The mistake is in the first sentence. Nothing unusual happens at 
23:59:59. One second later, at 23:59:60, the leap second begins. In 
other words, UTC will do this:


23:59:59.9
23:59:60.0
23:59:60.1
...
23:59:60.9
00:00:00.0

I have informed the author of the press release.

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Re: [LEAPSECS] USNO press release

2016-07-11 Thread Brooks Harris 
"WASHINGTON, DC -- On December 31, 2016, a "leap second" will be added 
to the world's
clocks at 23 hours, 59 minutes and 59 seconds Coordinated Universal Time 
(UTC). This
corresponds to 6:59:59 pm Eastern Standard Time, when the extra second 
will be inserted at the

U.S. Naval Observatory's Master Clock Facility in Washington, DC. "

It seems to me not exactly wrong, but misleading in several respects:

1) Its a *positive* Leap Second
2) "introduced" or "inserted" rather than "added" are better terms 
consistent with ITU-R 460.
3) The Leap Second is not, typically, "added to the worlds clocks" in 
the same way its introduced to UTC. If "world clocks" means "local time" 
the Leap Second will typically be introduced on the local timescales 
simultaneous with its occurrence on UTC.
4) "added .. at 23 hours, 59 minutes and 59 seconds" might be 
misinterpreted to mean *before*, or somehow together with, 23:59:59. 
"Inserted following" might be more clear.

5) there's no mention of what happens in the other USA time zones.

Its always a challenge to write about UTC in a way that's both clear and 
readable. Here's my go:


The International Earth Rotation and Reference Systems Service (IERS) 
has determined a positive Leap Second shall be introduced in the 
Coordinated Universal Time (UTC) timescale at the end of the day on 
2016-December-31. The positive Leap Second will be inserted immediately 
following the second labeled 23:59:59 and labeled 23:59:60. Most world 
clocks will introduce this positive Leap Second on their local 
timescales simultaneous with its occurrence in UTC. The U.S. Naval 
Observatory's Master Clock Facility in Washington, DC will insert this 
positive Leap Second to the Eastern Standard Time (UTC-05:00) timescale 
on 2016-December-31 immediately following the second labeled 06:59:59 pm 
(18:59:59) and will be labeled 06:59:60 pm (18:59:60).


-Brooks

On 2016-07-10 11:26 PM, Jonathan E. Hardis wrote:
I don't disagree with your interpretation of UTC, but there's no error 
in the announcement.  The leap second is */added/* */at /*23:59:59. 
 While the leap second itself is 23:59:60, it's during the interval 
23:59:59 when the logic is changed for what the next second should be 
labelled.


 - Jonathan


On Jul 10, 2016, at 3:39 PM, Paul Hirose > wrote:


On 2016-07-08 12:16, I wrote:

Is there a mistake in this announcement?


http://www.usno.navy.mil/USNO/tours-events/2016_Leap_Second%20Press%20Release%20-%20Final.pdf


WASHINGTON, DC -- On December 31, 2016, a "leap second" will be added to
the world's clocks at 23 hours, 59 minutes and 59 seconds Coordinated
Universal Time (UTC).


The mistake is in the first sentence. Nothing unusual happens at 
23:59:59. One second later, at 23:59:60, the leap second begins. In 
other words, UTC will do this:


23:59:59.9
23:59:60.0
23:59:60.1
...
23:59:60.9
00:00:00.0

I have informed the author of the press release.

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Re: [LEAPSECS] USNO press release

2016-07-10 Thread Jonathan E. Hardis 
I don’t disagree with your interpretation of UTC, but there’s no error in the 
announcement.  The leap second is added at 23:59:59.  While the leap second 
itself is 23:59:60, it’s during the interval 23:59:59 when the logic is changed 
for what the next second should be labelled.

 - Jonathan


> On Jul 10, 2016, at 3:39 PM, Paul Hirose  wrote:
> 
> On 2016-07-08 12:16, I wrote:
>> Is there a mistake in this announcement?
>> 
>> 
>> http://www.usno.navy.mil/USNO/tours-events/2016_Leap_Second%20Press%20Release%20-%20Final.pdf
>> 
>> 
>> WASHINGTON, DC -- On December 31, 2016, a “leap second” will be added to
>> the world’s clocks at 23 hours, 59 minutes and 59 seconds Coordinated
>> Universal Time (UTC).
> 
> The mistake is in the first sentence. Nothing unusual happens at 23:59:59. 
> One second later, at 23:59:60, the leap second begins. In other words, UTC 
> will do this:
> 
> 23:59:59.9
> 23:59:60.0
> 23:59:60.1
> ...
> 23:59:60.9
> 00:00:00.0
> 
> I have informed the author of the press release.
> 
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Re: [LEAPSECS] USNO press release

2016-07-10 Thread Steve Allen 
On Sun 2016-07-10T12:39:20 -0700, Paul Hirose hath writ:
> The mistake is in the first sentence. Nothing unusual happens at
> 23:59:59. One second later, at 23:59:60, the leap second begins.

It would be mildly amusing if this were blamed on an overzealous
autocorrect insisting that no such time exists.

--
Steve Allen  WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street   Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064   http://www.ucolick.org/~sla/   Hgt +250 m
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Re: [LEAPSECS] USNO press release

2016-07-10 Thread Paul Hirose 

On 2016-07-08 12:16, I wrote:

Is there a mistake in this announcement?


http://www.usno.navy.mil/USNO/tours-events/2016_Leap_Second%20Press%20Release%20-%20Final.pdf


WASHINGTON, DC -- On December 31, 2016, a “leap second” will be added to
the world’s clocks at 23 hours, 59 minutes and 59 seconds Coordinated
Universal Time (UTC).


The mistake is in the first sentence. Nothing unusual happens at 
23:59:59. One second later, at 23:59:60, the leap second begins. In 
other words, UTC will do this:


23:59:59.9
23:59:60.0
23:59:60.1
...
23:59:60.9
00:00:00.0

I have informed the author of the press release.

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Re: [LEAPSECS] USNO press release

2016-07-08 Thread Greg Hennessy 

On 07/08/2016 03:16 PM, Paul Hirose wrote:

Is there a mistake in this announcement?


http://www.usno.navy.mil/USNO/tours-events/2016_Leap_Second%20Press%20Release%20-%20Final.pdf


Perhaps. What do you think might be wrong?



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