This message was sent to the new email address as a test.
Our plan for the old web site on rom.usno.navy.mil is to place a
"leapseconds has moved" notice there.
-Original Message-----
From: Matsakis, Demetrios N.
Sent: Wednesday, January 31, 2007 7:59 PM
To: 'Leap Seconds I
There is a mistake in the viewgraphs, which the authors will correct in
any other reports they generate. This is the reference to URSI.
I was the person who chaired the URSI Commission J working group, and
later chaired the URSI-wide working group on the matter. Every report
noted that no signif
50353b2c...@echoex.timenet.usno.navy.mil>,
"Matsakis, Demetrios" writes:
>On the basis of six years of non-expression of interest from their
>constituency, the URSI secretariat made a unanimous decision to not
>respond to the ITU-R's Special Rapporteur Group's letter, and my
>
The best way to get "Time" out of GPS is to apply the leap seconds and
subframe 4 corrections of the broadcast GPS navigation message to GPS
time, and get UTC(USNO) via GPS. Most GPS receivers do this
automatically. There can be calibration and latency issues, which are
usually but not always belo
riginal Message-
From: Richard B. Langley [mailto:l...@unb.ca]
Sent: Thursday, December 18, 2008 1:14 PM
To: Leap Second Discussion List; Matsakis, Demetrios
Subject: Re: [LEAPSECS] WP7A status
Not just for navigation. The geodetic community time-tags GPS
measurements with GPS
(System) Tim
I agree with Tom about GPS. Over the past decade both GPS's delivered
prediction of UTC(USNO) and GPS time have been getting closer and closer to
UTC(USNO), modulo 1 second and as measured by the RMS. That is mostly due to
improved GPS clocks, but tighter steering was implemented about ten
Microsoft's NTP package gives no notice of a pending leap second, even
when acting as a server. Here are some pastes from Microsoft's web
site:
"The Windows Time service does not indicate the value of the Leap
Indicator when the Windows Time service receives a packet that includes
a leap second.
Here is a babblefish translation of the link:
Buenos Aires, oct 16 (Reuters) - the Argentine Government will not change to
the standard time east weekend, as it were predicted, said to Friday state
agency Télam, at moments at which the opposition of the provincial governments
grew.
"At the mom
I have no privileged information and GPS receiver programming is not what I do,
but I also have never known the ICD200 to be incorrect. Perhaps ten years ago,
two timing experts separately informed me of great frustration they had writing
their own GPS receiver software, but it turned out they
The concept of whether TAI is a product in itself, or just a step to generate
UTC, has led to some disagreements over time.
However, there is only one UTC, which has many realizations. The true UTC is
determined not from the realizations, but from the clocks behind those
realizations.
___
Discussion List
Subject: Re: [LEAPSECS] "UTC is derived from TAI"
On Sun 2010-03-14T21:11:58 -0400, Matsakis, Demetrios hath writ:
> However, there is only one UTC, which has many realizations. The
> true UTC is determined not from the realizations, but from the clocks
> behind
I asked an unquestioned expert on celestial navigation about its UT
requirements. This was his response:
For observed stars that are near the celestial equator or at low
declinations, the error can be up to 0.25 nm per uncorrected second.
This
is a systematic error, i.e., all lines of position f
I have now heard from two sources that the revised ITU-R draft
recommendation TF.460-6 passed a major hurdle in Geneva last week. It
will be sent by SG7 to the January 2012 Radiocommunication Assembly
meeting. At the Radiocommunication Assembly only countries that belong
to the ITU-R can vote and
It wouldn't surprise me if you have your kids build one of those for a science
fair project!
From: Tom Van Baak
Sent: Tue 10/26/2010 2:14 AM
To: Leap Second Discussion List
Subject: Re: [LEAPSECS] Saint Crispin's Day
...
And no, my lab isn't near as good as NIST; but I do keep
an eye out for
At the USNO, I had monthly meetings on Y2K problems starting in 1998.
Some were handled in software, and others required dealing with the
manufacturer. Our equipment that gave time to NTP via IRIG-B required a
special chip to prevent falling back 100 years upon restart. Some of
our GPS monitor eq
I can't help with the flying cars, but UTC does "deliver" a frequency
that is the most precisely and accurately measured quantity known to
humans. Time is the integral of that frequency, and over one
leapsecond-less day a frequency error of 1.E-12 corresponds to a time
error of 86400*1.E-12 = 86 n
Although I believe I included amateur astronomer concerns uncritically
in my URSI report on the leap seconds, I have always wondered how many
astronomers who are at the level of needing to correct for UT1 would not
be competent to do so. I would guess that most would consider doing so
part of the
Rumors that the USNO tried to insert a leap decade as an experiment are not
exactly correct. See the message in http://tycho.usno.navy.mil/ntp.html. One
of the 50-odd emails we got indicated that it would take working all night to
undo the damage. A few responded that it was a good lesson for
Rumors that the USNO tried to insert a leap decade as an experiment are not
exactly correct. See the message in http://tycho.usno.navy.mil/ntp.html. One
of the 50-odd emails we got indicated that it would take working all night to
undo the damage. A few responded that it was a good lesson for
Not my issue, but the last day of the 20th century is technically December 31,
2000.I wish it weren't. When this controversy passed in 1701, Isaac
Newton is quoted has having rejoiced that "the issue was finally behind us".
Also, I would add November 18, 1858 as the first day in the Modif
Sometimes it doesn't matter how much notice is given. This morning I got an
email from someone asking why his clock just jumped to daylight time.I've
had many emails from people whose clocks incorporate a change late, which could
be due to radio reception problems among other things. I've
http://www.timeanddate.com/news/time/paris-meridian-gmt-obsolete.html
-Original Message-
From: leapsecs-boun...@leapsecond.com [mailto:leapsecs-boun...@leapsecond.com]
On Behalf Of leapsecs-requ...@leapsecond.com
Sent: Thursday, April 03, 2014 12:01 PM
To: leapsecs@leapsecond.com
Subject:
ecific than "Re:
Contents of LEAPSECS digest..."
Today's Topics:
1. Re: Real April Fools' Joke: GMT Abolished (Rob Seaman)
--
Message: 1
Date: Mon, 7 Apr 2014 05:57:20 -0700
From: Rob Seaman
Subject: Re: [LEAPSEC
ssion List; Matsakis, Demetrios
Subject: Re: [LEAPSECS] Earth speeding up?
In message , "Mats
akis, Demetrios" writes:
>The best hand-waiving arguments I've heard for these recent "decadal
>fluctuations" is that the oblateness of the Earth is changing, possibly
With regards to Gerard's question (below), I think the answer is that his
timescale is one of a large class of possible timescales that could be given
any name desired as soon as anybody had a use for it. It would be trivial to
compute the calendar dates he talks about of course, but it's not
Tom,
I don't have any special predictive insights, but when I look at the data
things appear to be fairly flat.Although the length of day (LOD) has
dropped below 86400 in the recent summers, it didn't last year. As my
viewgraphs indicate, the best predictor for this kind of variation is
The marketplace.org article quotes Bob Tjoelker as saying his team, and
deep-space missions in general, can handle leap seconds. I've known Bob
Tjoelker for years. He's a super-scientist designing super-clocks. Since
some of those clocks are space-qualified, he is literally a rocket scienti
Leap Second Discussion List
Subject: Re: [LEAPSECS] The leap second, deep space and how we keep time -Brooks
> On Jan 28, 2015, at 2:33 AM, Martin Burnicki
> wrote:
>
> Warner Losh schrieb:
>>
>>> On Jan 27, 2015, at 7:18 PM, Steve Allen wrote:
>>>
>&
...@leapsecond.com] On Behalf Of Greg
Hennessy
Sent: Wednesday, January 28, 2015 4:50 PM
To: Leap Second Discussion List
Subject: Re: [LEAPSECS] The leap second, deep space and how we keep time -Brooks
On 01/28/2015 01:42 PM, Matsakis, Demetrios wrote:
> To Steve mostly,
>
> It would be misl
Steve,
I think this is quite an improvement. I agree with you about the median,
especially as many of the predictions are not necessarily independent. I
haven't reproduced the curves of your new plots, and I don't have a missing
estimate of DeltaT, but I have some suggestions:
1. The plot
Dr. Gernot Winkler passed on April 30. To this list he is well-known as the
person who, along with Dr. Essen of NPL. initiated the current system of leap
seconds in UTC. To us in the U.S. Naval Observatory's Time Service Department,
Gernot was an inspiring leader in every way. A strong and s
Look for a TV show on National Geographic or PBS called "Genius by Stephen
Hawking". Episode 1: Can We Time Travel?
It is at 9 PM in Washington DC
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I'm surprised nobody reacted to some of the things in Steve's email. It's
probably because 8 years is a long time (7 now).
With regards to the last paragraph, the support for Steve's inference seems
rather weak. I feel an obligation to point out that as far as I have seen my
employer, the U.
The quote below (from biblegateway.com) may imply a meteor shower also took a
toll on their adversaries.Perhaps someone should scan the area for
meteorites suitably below ground?
... having marched all night from Gilgal. 10 So the Lord routed them before
Israel, killed them with a great
>From the table in the reference provided by Paul Hirose's post
>(http://astro.ukho.gov.uk/nao/lvm/) , the uncertainty in delta-T is 0.4 hours.
> At a latitude of 31 degrees, I compute a (1-sigma) distance of 500 km, which
>the internet tells me is about as far away as Alexandria. Judging from
I was surprised to find phrases in the Lick web pages: "CCIR ignored the
advice that astronomers " and "squelched astronomers who insisted that leap
seconds would cause trouble".
I realize their author is not the only person with a strong emotional bias, but
even so I question the tone of t
Well, I can't match Tom's poetry but I note that the deregulation of
power-line-time makes the WWV-series even more critical. So far, though, I
haven't seen super-large changes in the timing of the 60 Hz signals coming into
the USNO. Seems like there was a net 30 second drop in June.
-Ori
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