Poul-Henning Kamp wrote:
Actually, I'm pretty sure time is entirely independent of which way you
orient the Earth.
Well, Ernst Mach and Albert Einstein might be among those who quibble :-)
Threads on this mailing list (and the original Navy list) have often made an
implicit assumption that
On Dec 15, 2010, at 7:49 AM, Tom Van Baak wrote:
As for your universal comment; that's problematic. I suspect
you will find many uses of that word which are quite unrelated
to astronomy; from universal studios to universal health case.
Lots of terminology is overloaded. The ITU on the other
On 12/18/2010 10:49, Finkleman, Dave wrote:
For everyone to criticize, I have almost convinced the USAF to issue a
position statement to OSD and the State Department pleading that UTC not
change from the current paradigm. The rationale is that UTC is called out
as the mandatory service
I wrote:
Then it should be straightforward to perform the inventory of the different
segments, systems, and software to demonstrate one or the other of these
assertions.
Poul-Henning Kamp wrote:
How many lines of code can you review per hour ?
The logic escapes me. The codebase and
Due diligence in system engineering should not be controversial.
... and it should come with a cost estimate.
So let's see. (Putting aside the actual system requirements for the moment.)
The comparative costs and risks of UTC without leap seconds are unknown
relative to the status quo (UTC
But you forget an important fact Rob: In computing UTC doesn't have leap
seconds presently.
Computing is not the only game in town. The world is layered on systems and
procedures that have assumed mean solar timekeeping for hundreds of years. The
codebase we have has evolved with this
On Dec 19, 2010, at 2:07 AM, Poul-Henning Kamp wrote:
In message 1292742460.31540.137.ca...@localhost, Paul Sheer writes:
For this and other reasons many programs implement their own function to
do this. They would assume 86400 seconds per day to copy POSIX or
because they have never heard
On Dec 19, 2010, at 2:58 AM, Poul-Henning Kamp wrote:
My estimate is that if we get 10 years advance notice, we can eliminate
90-99% of the software from the review, because the current POSIX hack can be
distributed preconfigured in operating systems.
On Dec 19, 2010, at 9:33 AM, Steve
watch is running backwards.
Rob Seaman
National Optical Astronomy Observatory
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On Dec 23, 2010, at 5:45 PM, Jonathan E. Hardis wrote:
WHERE under U.S. jurisdiction is UTC (no offset) the legal, civil time?
There's the ISS, but on the other hand does jurisdiction mean much until it
has been challenged in court?
Rob
___
Rob Seaman wrote:
Which is to say that mean solar time is a requirement. Leap seconds as we
currently know them are one possible way to implement that requirement. The
latter is negotiable. The former is not.
Warner Losh wrote:
Mean solar time is not a requirement. It is merely
On Dec 23, 2010, at 5:45 PM, Jonathan E. Hardis wrote:
WHERE under U.S. jurisdiction is UTC (no offset) the legal, civil time?
Cleaner answers still await, however.
Well, a little googling tells us that In Navy Cash, all dates and times are
recorded and reported in Greenwich Mean Time
I wrote:
Which is why the international civil timekeeping standard should be tied to
physical reality.
...but Poul-Henning Kamp said:
1. There is no international civil timekeeping, civil timekeeping is a
national legislative matter.
and later appeared to be arguing the exact opposite
Poul-Henning Kamp replies to...well, apparently himself:
...but Poul-Henning Kamp said:
1. There is no international civil timekeeping, civil timekeeping is a
national legislative matter.
and later appeared to be arguing the exact opposite:
The entire point of the Meter Convention and
God bless us, every one!
On Dec 26, 2010, at 8:40 PM, Richard B. Langley wrote:
Quoting Rob Seaman sea...@noao.edu:
The ITU, rather, have monomaniacally pursued one-and-only-one NON-solution
for a decade, and have assiduously avoided characterizing the problem they
claim to seek to solve
breath...
Rob Seaman
National Optical Astronomy Observatory
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On Dec 28, 2010, at 12:11 PM, Poul-Henning Kamp wrote:
I belive that the British 60kHz Rugby transmitter regularly have
been transmitting out-of-date DUT1 values due to sloppy procedures.
That would indicate that it is not a very important part of their data.
Not currently, perhaps...
On Dec 30, 2010, at 2:55 PM, Finkleman, Dave wrote:
He has communicated with OSD and my employer castigating my campaign for
consensus that considers the consequences.
Great alliteration!
His communication is all emotion and no substance.
Then it should be straightforward to refute.
He
by the monomaniacal ITU process.
Leap seconds are a means to an end. Civil timekeeping is based on mean solar
time. The ITU can cheat for some purposes for some users for some length of
time. The details of the proposed kludge matter. Those details should be
worked out in advance.
Rob
On Dec 30, 2010, at 5:06 PM, Jonathan E. Hardis wrote:
NO ONE is advocating a perpetual drift apart between atomic time and
universal time (sundial time).
On Dec 30, 2010, at 5:49 PM, Greg Hennessy wrote:
What do you base this on, since I think the ITU proposal is exactly that?
...the
in the only mailing list created for this
topic. Stop hiding under a rock.
Rob
--
On Dec 30, 2010, at 7:30 PM, Steve Allen wrote:
On 2010 Dec 30, at 18:24, Rob Seaman wrote:
Post the proposal. This is an international standard, discussions should be
public.
The ITU-R delegates are enacting
of the merits of its
notional position.
On Dec 30, 2010, at 9:04 PM, Jonathan E. Hardis wrote:
On Dec 30, 2010, at 7:41 PM, Rob Seaman wrote:
It is *hasty* to force a decision when the current definition of UTC is
viable for centuries.
... There are those who believe that the current definition
Clive D.W. Feather wrote:
Rob Seaman said:
FACT: civil timekeeping is ultimately tied to the synodic day (i.e., mean
solar time)
You make this claim regularly and label it fact. However, it is a claim,
not a fact.
Evolution is fact. The expansion of the universe is fact. Plate
Another New Year's Eve and the familiar talking points continue to swirl around
on the Leapsecs list. Let's try something different, a gedanken experiment.
Definition: The [SI] second is the duration of 9 192 631 770 periods of the
radiation corresponding to the transition between the two
Anybody going to the AAS in Seattle next week? I'll be staffing the VAO booth
all week (aside from a session here or there). We can plot world domination
through leap seconds. evil_cackle /
Rob
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Let's split the difference - maybe a milli? Not nearly as entertaining, drat!
(As you say, probably microseconds and the funny u-like character got lost on
the way to ASCII.)
--
On Jan 5, 2011, at 12:58 PM, Poul-Henning Kamp wrote:
In message 575fcbbd-13ca-4eb7-a620-9f076bea5...@noao.edu, Rob
(As you say, probably microseconds and the funny u-like character got lost
on the way to ASCII.)
I'm sure Greece will have you know that there is nothing funny about the
letter Mu :-)
So you're arguing that an international standard can be too simple to capture
the necessary complexity
No, I'm saying that people who write standards often don't know what they
should be doing.
Finally! Something we can agree on!
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On Jan 7, 2011, at 6:08 AM, Zefram wrote:
Currently, a June leap second can occur while far-east markets are open.
There is nothing magic about the end of the month scheduling. It has some
advantages, that's all.
DST adjustments on the other hand are (usually? always? some places?
On Jan 7, 2011, at 7:37 AM, Poul-Henning Kamp wrote:
As usual you try to fudge the fundamental facts to your point of view:
Get a good introductory astronomy text and a transparent celestial globe.
Spend some time understanding the differing natures of apparent solar time
and mean solar
Either someone out there is reading leapsecs - or somebody else is paying
attention. Either way it is a good thing :-)
--
Begin forwarded message:
From: central_bur...@iers.org
Date: January 7, 2011 8:40:47 AM MST
To: messa...@iers.org
Subject: IERS Message No. 180 - revised version
Currently local time zones range from Christmas Island, on Z+14:00, to Midway
Island, on Z-11:00 (I use Z to avoid the UTC/UT/GMT argument). So there's
always somewhere where it's not Sunday.
That should make Doctor Who aficionados happy. He never lands on Sunday.
(Perhaps he's trying to
, with the many possible solutions.
They have painted themselves into a corner with this mindset that there is only
one possible solution (and, I guess, many problems buzzing around like
mosquitos).
Rob Seaman
National Optical Astronomy Observatory
On Jan 7, 2011, at 9:36 AM, Warner Losh wrote:
On 01/07/2011 07:55, Rob Seaman wrote:
Eliminating leap seconds is an attempt to change the period of the day. But
the Sun says otherwise.
No. Eliminating leap seconds keeps the period of the day constant.
I didn't say the period of the day
On Jan 7, 2011, at 11:00 AM, Tony Finch wrote:
On Fri, 7 Jan 2011, Rob Seaman wrote:
It is a requirement - a description of the problem space - that manifold
human activities are loosely or tightly coupled to the synodic day.
Which? UTC with leap seconds is tightly coupled to the day
will historians or lawyers
consult to learn the applicable timezone offsets that were in force in some
location(s) during some epoch(s) in question?
Rob Seaman
National Optical Astronomy Observatory
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http
Back home in Tucson from the American Astronomical Society meeting. Glad to
see a rousing discussion, but I can't say that my heart is in unraveling the
several threads. Instead, permit me to pose a question.
Demetrios Matsakis, the founder of this list, wrote:
I can't help with the flying
On Jan 14, 2011, at 2:40 PM, Poul-Henning Kamp wrote:
In message f1c36c4f-a32a-4ebb-bfde-c51c8a156...@noao.edu, Rob Seaman writes:
My answer has always been that both are necessary. Leap seconds are one
possible way to reconcile these very different flavors of time
I'm delighted to see new life pumped into the discussion.
Regarding UTC-SLS, for context I might recommend Mark Calabretta's
contributions that were chiseled on the stone tablets of the original mailing
list:
Leap-seconds, the epsilon perspective:
On Jan 28, 2011, at 3:57 PM, Poul-Henning Kamp wrote:
In message 489a36d6-3f2d-45b1-9a11-58d596a63...@noao.edu, Rob Seaman writes:
Civil time is based on the synodic day.
Civil time is under the control of local government and you have no
business telling any country but your own what
On Jan 28, 2011, at 4:48 PM, Poul-Henning Kamp wrote:
In message fe4f54ac-7e6b-4d3c-8a40-b2d67d69b...@noao.edu, Rob Seaman writes:
On Jan 28, 2011, at 4:17 PM, Warner Losh wrote:
Sometimes I think we should define a second that's 1e-11 or so shorter so
that the problems of leap seconds
IOW: the only way you will take my non-SI rubber seconds from me is from
my cold dead hands.
One hopes this is hyperbole (alternative explanations are troubling). It is
unlikely to aid your professed position.
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On Jan 30, 2011, at 3:44 AM, Stephen Colebourne wrote:
In other words, I flat out don't believe that the tinkering with time would
stop simply because leap-seconds were stopped.
This is an insightful observation. What does the ITU believe will happen
should they succeed? (Perhaps I should
On Jan 31, 2011, at 1:07 AM, Poul-Henning Kamp wrote:
I pointed out a long time ago, that if astronomers played their cards right,
this would be a funding opportunity for much needed renovations...
Bwa-ha-ha-ha!
Calling any such new timescale something other than UTC (or not
UT-anything,
On Jan 31, 2011, at 8:59 AM, Poul-Henning Kamp wrote:
In message 12988684-b911-481b-b557-90e55cd73...@noao.edu, Rob Seaman writes:
On Jan 31, 2011, at 1:07 AM, Poul-Henning Kamp wrote:
Is there really a requirement to render the concept of universal time
meaningless? Or is UTC merely
On Jan 31, 2011, at 9:46 AM, Tony Finch wrote:
Remember that the politicians already have a mechanism to adjust their local
time to match the hours of daylight to their satisfaction. Time zones are not
going away.
Yes, politicians control local time. UTC is not local. Smooshing time zones
On Jan 31, 2011, at 11:33 AM, Poul-Henning Kamp wrote:
And you don't think a software update in the next 8-10 years could fix that
issue, given that DoD is likely to lean on the vendor to get this fixed ?
Fix is not the right word for something that is not currently broken.
That said, it is
The threads are coming fast and furious and one has to choose what to reply to.
On Jan 31, 2011, at 11:25 PM, Tom Van Baak wrote:
The issue here is one man's distant horizon is another man's pending disaster
and the list has shown there is no convincing either side.
I'd say rather that we
On Feb 1, 2011, at 11:09 AM, Poul-Henning Kamp wrote:
But Universal Time is *inherently* unpredictable. (That's its charm :-)
No, that's merely an artifact of how it is defined.
Note I said Universal Time not UTC. If you haven't picked up on the subtle
vibe, the astronomers here are
to be to use UTC as a Nelson's
Bridge to ultimately deprecate TAI.
For precision timekeepers they appear to have remarkably little respect for the
precise meaning of time.
Rob Seaman
National Optical Astronomy Observatory
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Poul-Henning Kamp wrote:
They might just call the new leap-less timescale
Unified Time for Communication
What would that be in French? Probably Temps something something, right?
The acronym would presumably have to avoid both UTC for the English and Txx for
the French. Maybe CUT
Stephen Colebourne wrote:
This list is good at disagreeing, but given the brainpower here, perhaps some
consensus building might be good? I'll try one approach, and see what happens.
This is a good creative problem solving exercise. We tried various other
approaches back in the day:
Um - as I said I will refrain from comment on the assertions. However, I also
said a glossary might be a good idea. The SI second is a well defined
concept. These others certainly have no normative force. In particular, the
essence of the problem in front of us is that the Gregorian
I'm trying not to comment on every one (of the very many) issues I see with
this thread. The point of the exercise is to seek consensus. As Stephen said
at the very beginning, this group is very good at identifying points of
disagreement.
Note that Descartes started with a single
Warner Losh wrote:
I'd love to kill leap seconds. Lots of my problems go away if they are just
gone.
However, if that isn't possible, I'd be happier with a loser bounds on DUT1
that targets 0.5s but can accept up to 2s of drift if the benefit from that
loser tolerance is a 10 year or
Tony Finch wrote:
If you have a good clock you can work out the equation of time. If your
reference is a sundial you can set a bad clock to mean solar time using the
equation of time.
An excellent exposition of why our civilization's fundamental time reference
should be a big gaudy
Tony Finch wrote:
the whole point of universal time is that it's the default timscale
for civil use and only specialists should need anything else.
Stephen should add this to the consensus building list.
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On Feb 7, 2011, at 12:37 PM, Finkleman, Dave wrote:
Unfortunately, some operators don't know what is inside the black box. We
accommodate this by requiring the fields but not the real content. If
geopotential info fields are filled with default characters, we know that
this idiot doesn't
Warner Losh wrote:
On 02/07/2011 14:03, Rob Seaman wrote:
Tony Finch wrote:
the whole point of universal time is that it's the default timscale
for civil use and only specialists should need anything else.
Stephen should add this to the consensus building list.
Yes. Along
Warner Losh wrote:
Might be a better way to put it. Civilian time users just need to agree on
what time it is amongst the various parties. Everything else is a second
order effect.
We seem to be debating again, rather than seeking assertions of consensus :-)
Parties are not necessarily
Tony Finch wrote:
the whole point of universal time is that it's the default timscale
for civil use and only specialists should need anything else.
Seeking consensus, I said:
Stephen should add this to the consensus building list.
Tony said:
Does that mean that you agree that its very
I said:
Civil timekeeping is a worldwide system.
Poul-Henning Kamp wrote:
No it is not.
It is remarkable how the most aggressive responses to my posts are when I
mention system engineering or best practices or otherwise suggest that this
is fundamentally an exercise in proper system
Warner Losh wrote:
The current ITU proposal would have the effect of moving the coupling of the
Earth's rotation from the time that is broadcast (now called UTC) to the
timezones that local governments promulgate.
This would be chaos for anyone needing to compare timestamps in different
Poul-Henning Kamp wrote:
Sometimes it is civil, sometimes it is military, most of the time it is
corporate.
We have frequently debated vocabulary here. This is why I suggested a glossary
would be a good idea.
Civil timekeeping has often been taken to mean something like the common
Warner Losh wrote:
How would it be any different than today? Every few hundred years, the
government moves the time zone. Heck, they do that now every few years
anyway. Each government would be able to move it as they saw fit, or follow
other government's leads. If the US move and
Warner Losh replies:
A) It would be taking what is currently a doubly indirect pointer and
removing the layer in the middle. Dereferencing (converting to UTC) would
no longer return a timescale stationary with respect to the synodic day.
I don't see why it wouldn't. If you really need
Tony Finch wrote:
Warner Losh wrote:
Rob Seaman wrote:
C) As pointed out on numerous occasions in the past, these kaleidoscopic
timezones would accelerate quadratically just like leap seconds.
This problem isn't solved by this method either. True.
Except that timezone adjustments
Poul-Henning Kamp wrote:
What authority would that be, and what powers would it have ?
Per SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE
REFERENCE, we know that:
NO positive leap second will be introduced at the end of June 2011.
I don't need to remind you, that
Oooh! Google Sagnac and you also get lots of trendy pseudoscience from sites
like anti-relativity.com. What fun!
--
On Feb 10, 2011, at 4:01 PM, Mark Calabretta wrote:
On Thu 2011/02/10 07:18:53 -0800, Tom Van Baak wrote
in a message to: Leap Second Discussion List leapsecs@leapsecond.com
On Feb 10, 2011, at 5:39 PM, Warner Losh wrote:
Without a plan, people will keep doing what they are doing now. Today's code
might not be around in 10k years, but if people don't come up with a plan,
then code written 1k or 5k years from now will still have the same problems.
I think the
Something else is wrong here too. National UTC timing labs
are all over the world, at a variety of latitudes and altitudes.
No one corrects for latitude as far as I know; only altitude.
Then there's Relativistic Time Shifts for 'Flying Clocks':
On Feb 11, 2011, at 8:42 AM, Tony Finch wrote:
See for example
http://six.pairlist.net/pipermail/leapsecs/2011-January/002124.html
where Rob Seaman wrote Civil timekeeping is cumulative. Tiny mistakes
posing the problem will result in large and growing permanent errors.
Great to see folks
motivation of
allowing TAI to be suppressed is bad on top of bad on top of bad.
Understand the problem, engineer a solution, skip the politics and drama.
We should take our time and get it right.
Rob Seaman
National Optical Astronomy Observatory
What's the point?
Two links to refresh the discussion:
http://www.springerlink.com/content/g216411573882755/
http://maia.usno.navy.mil/eopcppp/eopcppp.html
Paul Sheer wrote:
I think what you will find is that there is no technical difference between
moving leap seconds into
Ian Batten wrote:
The UK's standard time broadcast, which is funded by the government, contains
DUT1 in a format which doesn't permit |DUT1|0.9.
The point is that the state of the art appears to allow the prediction of UT1
to better than 0.1s over 500 days - perhaps even better than 0.05s
On Feb 15, 2011, at 2:31 PM, Warner Losh wrote:
On 02/15/2011 09:12, Rob Seaman wrote:
So, what is the state of the art for long term predictions of UT1? Could
the algorithms used by the EOP PCC teams simply be run on the historical
Bulletin B numbers to find out?
At the Torin
Mark Calabretta wrote:
It would be circular then to compare the predictions against EOP C04 itself.
My point is just that archival data is sufficient to characterize the real
world behavior of the algorithms already developed. We needn't wait ten years
to know if data limited to what was
Warner Losh wrote:
Applying the short-term models that work really well for 500 days (that
result in an error bar of about 100ms) to long-term works adequately well for
most people, but would exceed the 1s tolerance in the 1000-1500 day time
frame due to the list of factors that you've
On Feb 19, 2011, at 9:08 AM, Joe Gwinn wrote:
This is all true, but solves a problem that the POSIX Committee neither
understood nor cared about.
Just as we needn't care about POSIX when advocating a simple but significant
improvement to the current leap second scheduling paradigm. There
On Feb 19, 2011, at 2:46 PM, Joe Gwinn wrote:
This would go a long way to resolving the POSIX objections.
Excellent - more consensus!
If such an approach is in fact adopted, and I very much doubt that the
Timelords much care about POSIX.
Indeed. Perhaps no more than they care about UTC
On Feb 22, 2011, at 3:04 PM, Warner Losh wrote:
while the leap-year code is:
return (year % 400) == 0 || (year % 4 == 0 year %100 != 0)
which will last us about a thousand years.
Define last us. Historical date comparisons require knowledge of how the
calendar has evolved in
On Feb 22, 2011, at 2:31 PM, Warner Losh wrote:
the 10-year horizon solves many problems with leap seconds.
I just wanted to highlight that significant consensus has indeed been reached!
Rob
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On Mar 4, 2011, at 2:55 AM, Tony Finch wrote:
No, posix time is UT and timezones are based on UT.
Just to be clear, the ITU has no putative or actual authority over a time scale
called UT. If POSIX requires Universal Time, and if POSIX has any actual
pertinence to the UTC shenanigans (rather
:
On Fri, 4 Mar 2011, Rob Seaman wrote:
If POSIX requires Universal Time, and if POSIX has any actual pertinence
to the UTC shenanigans (rather than just being a convenient talking
point) - well, then - UTC must remain UT.
That's backwards. POSIX is UT because UT is the basis of civil time
),
implementing the draft in front of the ITU will result in widespread pernicious
- dangerous - confusion immediately, as well as a massive mess to clean up -
whether in a decade, a century or a millennium.
Rob Seaman
National Optical Astronomy Observatory
Poul-Henning Kamp wrote:
I don't really care what your definition of is is,
No, but Tom apparently does. (See next reply.)
The civil day starts and stops whenever the most powerful civil
authorities for a given locality decide it should do so.
Civil day - singular - certainly cannot mean
On Mar 7, 2011, at 11:27 AM, Poul-Henning Kamp wrote:
I do not now and have never in the past suspected the ITU of competence.
But that does not prevent me, from supporting one of their proposals, if it
pulls in the right direction.
By contrast I suspect the ITU is quite competent - in
Warner Losh wrote:
This mapping is both lossy (because you can't undo it unambiguously) and
ambiguous (since the standard insists that leap seconds don't exist).
Lossy isn't quite the right word. Unfortunately the only antonym offered for
idempotent is changed.
The point being that lossy
I'm not sure we need new vocabulary, however note that dispredictable wouldn't
include the meaning of not subject to study. This recent preprint:
http://xxx.lanl.gov/pdf/1102.0212
offers ten possible explanations On the anomalous secular increase of the
eccentricity of the orbit of
Ask Bjørn Hansen wrote:
In the field of making stuff work it's important that the protocol for any
exception or failure scenario is as simple as possible.
Indeed:
http://catless.ncl.ac.uk/Risks/25.81.html#subj9.1
Leap seconds sound simple; but they aren't.
The cessation of leap
Poul-Henning, Howdy!
What the Italians did is called Forgetting history which is far more common
and very often perfectly acceptable, than the far more insidious charge you
level.
Um, Steve's message ended with: I suggest that anyone who wants not to forget
history should grab a copy of
On Apr 7, 2011, at 9:56 AM, Steve Allen wrote:
PHK's article seems to be here
http://queue.acm.org/detail.cfm?id=1967009
Various comments have been added to this article. The ACM glommed my golden
paragraphs into one block of text, unfortunately.
PHK infers that SouLShadow is an
Hi Tom,
Help me out here. That ACM generated time-stamp in your posting; which is it
by your definition: time-of-day or interval timekeeping?
Universal time is time-of-day. The current definition of UTC permits it to be
used to recover an interval timescale. Timestamps supply information
Poul-Henning Kamp wrote:
Tom Van Baak writes:
Rob Seaman wrote:
It is simply fact that time-of-day and interval timekeeping are two
different things.
Help me out here. That ACM generated time-stamp in your posting; which is it
by your definition: time-of-day or interval timekeeping
Warner Losh wrote:
Rob Seaman wrote:
Universal time is time-of-day. The current definition of UTC permits it to
be used to recover an interval timescale. Timestamps supply information
about both time-of-day and an interval since an epoch. More to the point
the interval may
Poul-Henning Kamp wrote:
Rob Seaman writes:
The day in time-of-day is the synodic day.
You keep stating this as a bare fact, without any kind of substantiation,
Please consult 100 other messages. The days counted by our calendars are
synodic days. Length-of-day is not an arbitrary
Tony Finch wrote:
GMT hasn't been maintained for decades.
Which seems a pretty good argument for UTC to remain defined as and be
maintained as a type of Universal Time. That is, for the general concept of UT
not to be allowed to become ambiguous. How does one refer to TCFKAUT (The
Concept
Steve Allen wrote:
Keith Winstein hath writ:
Rob Seaman wrote:
Remember, UT1 is only known retroactively.
To be fair, isn't this true of UTC (and TAI) as well?
But there are (multiple) realized and disseminated forms of UTC
Yeah - I thought twice about mentioning UT1, and presumably
Tony Finch wrote:
I don't see how. GMT was just a realization of UT2 (ish).
No. GMT was (and is) a widely used term by the general public. By comparison,
UT2 is a linguistic (and technical) footnote. Read Sobel's Longitude.
Greenwich Mean Time is a major historical story. Stories need
Tony Finch wrote:
I see no big difference from the current ambiguity of the terms UT and GMT
and UTC. You seem to be complaining that people who don't care about
precision will use imprecise terms ambiguously.
Currently they are variations of the same concept. Yes, there is a difference
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