On Sun, 8 Jan 2006, Tom Van Baak wrote:
> between astronomical and atomic timescales.
Could we rephrase that "between geophysical and atomic timescales" ?
Astronomers measure it and have to compensate for it, not cause it.
Reminds me bitterly of the widely reported loss of Mars Climate Orbiter
In message: <[EMAIL PROTECTED]>
John Cowan <[EMAIL PROTECTED]> writes:
: > But how in practice is it envisaged that a scheme
: > for migrating time zones versus TAI would work, precisely?
:
: Straightforwardly. Each locality decides when and how to adjust both
: its offset from TAI and
On Jan 9, 2006, at 12:03 AM, John Cowan wrote:
Each locality decides when and how to adjust both its offset from
TAI and its seasonal transition function (if any), just as it does
today.
Not just as today, see intervening messages.
What we abandon is a universal time tightly synchronized to
In message <[EMAIL PROTECTED]>, Rob Seaman writes:
>As I pointed out close to five years ago, the ultimate long term
>remediation will likely involve redefining the length of the second:
Rob,
I think this shows how little you understand of the entire thing.
Several SI units are defined relativ
Poul-Henning Kamp scripsit:
> Windows have got it right now I belive, but it used to be that a
> file created and transmitted from Denmark at the end of the business
> day would be older than a file created at the start of business day
> in California, despite a strict ordering of the events.
It'
Rob Seaman scripsit:
> >Sure, and you can timestamp then on either timescale, because there
> >is a 1 to 1 translation between the two timescales [1].
>
> Perhaps I miss your meaning here, too. The event of migrating a time
> zone is a discontinuity just as with a leap second or leap hour.
Sure.
In message <[EMAIL PROTECTED]>, Tom Van Baak writes:
>The danger, though, is that in the 60s maybe ten systems
>were affected by leap seconds. In the 80s maybe a
>thousand. Today, the number of systems affected (or is
>it infected?) with leap second awareness is in the millions.
>
>I worry about t
In message <[EMAIL PROTECTED]>, Rob Seaman writes:
>> Sensibly designed operating systems keep time in the form of the
>> first stage clock,
>
>Perhaps. We have no examples of this. Stage one would be TAI. As
>we have just been reminded, TAI is "not ready for prime time".
Stop.
You yourself d
Rob Seaman scripsit:
> The question is: how precisely does this differ from the situation
> now or in the past? Whether by fiat or not, some common worldwide
> "stage two" clock must exist.
Again, no it doesn't need to exist.
We need a uniform time scale like TAI. And we need local civil time
On Jan 8, 2006, at 6:41 PM, Tom Van Baak wrote:
am not sure I like the idea that eventually my car, traffic lights,
airlines, television, and my thermostat will have to be reliably
tied to the IERS in order to function properly.
This is a general issue with the increasingly tight coupling betw
> > You cannot divide timekeeping, time dissemination,
> > into neat stages. In the 1960s if ten labs were told
> > to offset their phase or frequency it affected only a
> > handful of people or systems. Today when IERS
> > announces a leap second, millions of machines,
> > systems, and people are
On 8 Jan 2006 at 15:04, Tom Van Baak wrote:
> You cannot divide timekeeping, time dissemination,
> into neat stages. In the 1960s if ten labs were told
> to offset their phase or frequency it affected only a
> handful of people or systems. Today when IERS
> announces a leap second, millions of mac
On Jan 8, 2006, at 4:04 PM, Tom Van Baak wrote:
You cannot divide timekeeping, time dissemination, into neat stages.
Again. My point is strengthened. This being the case, a requirement
on one "flavor" of time transfers to others. We will not solve the
problem of creeping complexity and inte
> Without further debating the meaning of "civil time", consider the
> implications of this two stage system. The first stage conveys TAI
> or something related to it by a constant offset. The second stage at
> any location (correct me if I misunderstand you) would be a secondary
> clock dissemin
On Jan 8, 2006, at 12:48 PM, Poul-Henning Kamp wrote:
What you overlook here is that computers tend to trancend
governmental boundaries.
This only strengthens my arguments. Anything that ties the world
together more tightly functions to create a single world "stage two"
system.
Sensibly des
> Research-quality telescopes, in particular all the ones built in the last
> few decades on alt-azimuth mounts, do of course use UT1; a 0.9s error
> would be a complex ~10 arcsec error in both axes and give a quite useless
> pointing performance. However, UTC is often used as a UT1 delivery
> sys
> : As I understood it, it was mainly that TAI is a post-factum "postal"
> : timescale.
>
> How is it that UTC can be realized in realtime, but TAI isn't. I
> thought the difference between the two was an integral number of
> seconds, by definition. Is that understanding flawed?
>
> Wanrer
Not f
On Sun 2006-01-08T11:44:04 -0700, M. Warner Losh hath writ:
> How is it that UTC can be realized in realtime, but TAI isn't. I
> thought the difference between the two was an integral number of
> seconds, by definition. Is that understanding flawed?
I believe the claim would be that UTC(insert y
In message <[EMAIL PROTECTED]>, Rob Seaman writes:
>On Jan 8, 2006, at 9:09 AM, Poul-Henning Kamp wrote:
>
>> Doing so would once and for all have to divorce earth orientation
>> from that unified time scale, leaving it to governments to align
>> civil time with daylight as they see fit (just like
In message: <[EMAIL PROTECTED]>
"Poul-Henning Kamp" <[EMAIL PROTECTED]> writes:
: In message <[EMAIL PROTECTED]>, Ed Davies writes:
: >Wow, things have got really stirred up around here. Lots of interesting
: >points but I'll just concentrate on one...
: >
: >Poul-Henning Kamp wrote:
:
On Jan 8, 2006, at 9:09 AM, Poul-Henning Kamp wrote:
Doing so would once and for all have to divorce earth orientation
from that unified time scale, leaving it to governments to align
civil time with daylight as they see fit (just like today).
Without further debating the meaning of "civil tim
In message <[EMAIL PROTECTED]>, Peter Bunclark writes:
>On Sun, 8 Jan 2006, Poul-Henning Kamp wrote:
>> finger [EMAIL PROTECTED]
>
>You mean [EMAIL PROTECTED] That would be quiet useful. Otherwise let's not
>bother with NTP protocol, just [EMAIL PROTECTED]
I don't really care what the ser
In message <[EMAIL PROTECTED]>, Rob Seaman writes:
>On Jan 8, 2006, at 5:38 AM, Poul-Henning Kamp wrote:
>
>> As I understood it, it was mainly that TAI is a post-factum
>> "postal" timescale.
>
>One is left pondering the fact that UTC is now (and would remain
>under any changes I've heard suggeste
In message <[EMAIL PROTECTED]>, Steve Allen writes:
>On Sat 2006-01-07T21:20:33 +0100, Poul-Henning Kamp hath writ:
>> Well, the BIPM doesn't really want anybody to use TAI, their director
>> said as much last year
>
>The Italian contribution to the November 2005 WP7A meeting could be
>interpreted
In message <[EMAIL PROTECTED]>, Steve Allen writes:
>> Something as simple as
>>
>> finger [EMAIL PROTECTED]
>>
>> Or even just a more stringent formatting of the bulletins on the ftp
>> site could do it as well.
>
>I do not believe that any of the IERS bureaus have internet
>connections a
On Jan 8, 2006, at 5:38 AM, Poul-Henning Kamp wrote:
As I understood it, it was mainly that TAI is a post-factum
"postal" timescale.
One is left pondering the fact that UTC is now (and would remain
under any changes I've heard suggested) a time scale based on TAI.
What magic makes one acceptab
On Jan 8, 2006, at 4:41 AM, Poul-Henning Kamp wrote:
It sounds to me like BIPM ought to make an Internet service
available which will deliver UT1 to astronomers in a timely fashion ?
Not sure BIPM is necessarily the appropriate agent, but otherwise
agree 100%. Perhaps we should seek other are
On Sat 2006-01-07T21:20:33 +0100, Poul-Henning Kamp hath writ:
> Well, the BIPM doesn't really want anybody to use TAI, their director
> said as much last year
The Italian contribution to the November 2005 WP7A meeting could be
interpreted a suggestion that the international agencies in charge of
On Jan 7, 2006, at 11:01 PM, M. Warner Losh wrote:
This would phase in the predictive timeline for leap second
insertions, and would also give the IERS control to end the
experiment if the time horizons exceeded their ability to predict
with confidence.
it would also be completely within the c
Poul-Henning Kamp wrote:
Well, the BIPM doesn't really want anybody to use TAI, their director
said as much last year, and I can see where he is coming from on that
one.
Ed Davies asked:
Since the usual response of the pro-leap second lobby to people
who want a uniform timescale is "use TAI" t
On Sun, 8 Jan 2006, Poul-Henning Kamp wrote:
> finger [EMAIL PROTECTED]
You mean [EMAIL PROTECTED] That would be quiet useful. Otherwise let's not
bother with NTP protocol, just [EMAIL PROTECTED]
Pete.
On Sun 2006-01-08T12:41:21 +0100, Poul-Henning Kamp hath writ:
> It sounds to me like BIPM ought to make an Internet service available
> which will deliver UT1 to astronomers in a timely fashion ?
That would have to be the IERS.
> Something as simple as
>
> finger [EMAIL PROTECTED]
>
> Or
In message <[EMAIL PROTECTED]>, Ed Davies writes:
>Wow, things have got really stirred up around here. Lots of interesting
>points but I'll just concentrate on one...
>
>Poul-Henning Kamp wrote:
>> Well, the BIPM doesn't really want anybody to use TAI, their director
>> said as much last year, and
Wow, things have got really stirred up around here. Lots of interesting
points but I'll just concentrate on one...
Poul-Henning Kamp wrote:
Well, the BIPM doesn't really want anybody to use TAI, their director
said as much last year, and I can see where he is coming from on that
one.
Since th
In message <[EMAIL PROTECTED]>, Peter Bunclark writes:
>On Sat, 7 Jan 2006, Poul-Henning Kamp wrote:
>Research-quality telescopes, in particular all the ones built in the last
>few decades on alt-azimuth mounts, do of course use UT1; a 0.9s error
>would be a complex ~10 arcsec error in both axes a
On Sat, 7 Jan 2006, Poul-Henning Kamp wrote:
>
> What Astronomers use UTC for, in your own many times repeated words,
> is "a convenient approximation of UT1", and consequently it follows
> that if instead of an approximation astronomers used the Real Thing,
> leap seconds could harmlessly be remov
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