So when I was googling around for more information about what paper
timescales the BIPM publishes, I found this:
http://iag.dgfi.badw.de/fileadmin/IAG-docs/Travaux2013/08_BIPM.pdf
which says:
The algorithm used for the calculation of time scales is an iterative
process that starts by
Alex Currant via LEAPSECS leapsecs@leapsecond.com wrote:
Despite what the recommendations might say, I think the TA(k) reported
in the Circular T are not efforts by lab K to realize TAI, since it is
hard to imagine how a lab could get a different offset attempting to
realize TAI from
On 2014-11-05 15:30, Warner Losh wrote on the
determination of TAI - UT1:
Now, back to the SI second vs the UT1 second. The UT1 second is 1E-8 or 1E-9
different
from the SI second. Unless they are computing the results to 7 or more digits,
the answers
will be identical, no matter which
Alex Currant via LEAPSECS wrote:
Despite what the recommendations might say, I think the TA(k) reported
in the Circular T are not efforts by lab K to realize TAI,
Indeed. TA(k) are independent time scales, apparently not steered in
either phase or frequency. They in fact run at a variety of
michael.deckers via LEAPSECS wrote:
The IERS certainly won't fudge on their units.
I'm afraid they do. Everyone does in this area. Even the IAU resolutions
fudge the units.
However, Warner is *also* fudging units, in a different manner, and I
think that's causing you trouble. Warner has said
Michael Deckers via LEAPSECS wrote:
The symbol TAI(k) is defined in
RECOMMENDATION ITU-R TF.536-2: Time-scale notations
of 2003 with the text:
TAI(k): Time-scale realized by the institute k and defined
by the relation TAI(k) = UTC(k) + DTAI,
Oh cool, same as my definition.
Zefram zef...@fysh.org wrote:
Warner has said things like the UT1 second is 1e-9 different from the
SI second. That statement implies that the UT1 second is a physical
quantity, with dimensionality of proper time, which can thus be measured
using the SI second as a unit.
The UT1 second is
Warner Losh wrote:
On Nov 5, 2014, at 10:54 AM, Zefram zef...@fysh.org wrote:
TAI(k) = TAI + (UTC(k)-UTC) = UTC(k) + (TAI-UTC)
Except that's not how others define it.
Michael Deckers has now pointed at ITU Rec TF.536-2 which defines TAI(k)
in the same way as I do. What conflicting
Bonjour,
Michael Deckers via LEAPSECS leapsecs@leapsecond.com wrote:
|On 2014-11-05 11:28, Steffen Nurpmeso wrote:
| Oh, the German Physikalisch-Technische Bundesanstalt (PTB) also
| has a general -- at least -- overview of the set of problems.
| (English: [1] and all around that; oops,
On Thu, Nov 6, 2014 at 8:38 PM, Tony Finch d...@dotat.at wrote:
The UT1 second is 2pi/86400 times the reciprocal of the angular velocity
of the Earth. The units for this quantity are just seconds (because angles
are dimensionless), or if you want to be more explicit, seconds per
2pi/86400
In message CAHZk5WfKSLMy77HK1Vsvk9PQ5v=tpb0rzuri8j4kmcezooa...@mail.gmail.com
, Sanjeev Gupta writes:
Note that seconds are also a unit of angles, so UT1 seconds being a
measure of angle is not strange.
...and I'm sure any surveyor or ships navigator would be extremely suprised
if
On Nov 5, 2014, at 7:57 PM, Alex Currant via LEAPSECS leapsecs@leapsecond.com
wrote:
Despite what the recommendations might say, I think the TA(k) reported in the
Circular T are not efforts by lab K to realize TAI, since it is hard to
imagine how a lab could get a different offset
On Nov 6, 2014, at 4:40 AM, michael.deckers via LEAPSECS
leapsecs@leapsecond.com wrote:
On 2014-11-05 15:30, Warner Losh wrote on the
determination of TAI - UT1:
Now, back to the SI second vs the UT1 second. The UT1 second is 1E-8 or 1E-9
different
from the SI second. Unless they
On Nov 6, 2014, at 5:09 AM, Zefram zef...@fysh.org wrote:
My view is that the UT1 second is a unit, not a variable quantity.
It's a different unit from the SI second, and can't be described in
terms of the SI second. If anything it's a unit of angle, and so can be
described in radians or an
On Nov 6, 2014, at 5:55 AM, Zefram zef...@fysh.org wrote:
Warner Losh wrote:
On Nov 5, 2014, at 10:54 AM, Zefram zef...@fysh.org wrote:
TAI(k) = TAI + (UTC(k)-UTC) = UTC(k) + (TAI-UTC)
Except that's not how others define it.
Michael Deckers has now pointed at ITU Rec TF.536-2 which
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
minutes and seconds are fractions of 60 and have been so since
babylonian times for minutes and since 13-mumble for seconds.
The etymology is actually helpful in this case rather than misleading as
etymologies so often are.
minute is short for pars
On Thu, Nov 6, 2014 at 10:37 PM, Poul-Henning Kamp p...@phk.freebsd.dk
wrote:
In message CAHZk5WfKSLMy77HK1Vsvk9PQ5v=
tpb0rzuri8j4kmcezooa...@mail.gmail.com
, Sanjeev Gupta writes:
Note that seconds are also a unit of angles, so UT1 seconds being a
measure of angle is not strange.
...and
Warner Losh wrote:
The conflicting definitions I've seen
have been from one of the time scientists that helped to setup TAI when he was
at NBS(later NIST) who strenuously instructed me that they weren't equivalent
and
was quite patient with my stupid
Tony Finch said:
minutes and seconds are fractions of 60 and have been so since
babylonian times for minutes and since 13-mumble for seconds.
The etymology is actually helpful in this case rather than misleading as
etymologies so often are.
minute is short for pars minuta prima, the first
If you want to go all the way back, Sumerian clay tablets arranged numbers
in a grid that looked a lot like a modern spreadsheet, and one unit in a
given column was equivalent to 60 units in the column immediately to the
right.
-Original Message-
From: LEAPSECS
On Nov 6, 2014, at 11:24 AM, Dennis Ferguson dennis.c.fergu...@gmail.com
wrote:
On Nov 6, 2014, at 11:19, Clive D.W. Feather cl...@davros.org wrote:
Tony Finch said:
minutes and seconds are fractions of 60 and have been so since
babylonian times for minutes and since 13-mumble for
On 2014-11-06 13:10, Steffen Nurpmeso wrote
in defense of the description by the German metrology
laboratory in [https://www.ptb.de/cms/en/fachabteilungen
/abt4/fb-44/ag-441/coordinated-universal-time-utc.html]:
Hm, indeed a sloppy translation of the original German text
Die
On 2014-11-04 22:26, Steve Allen quoted Bernard Guinot
about the unit for the difference TAI - UT1:
Guinot explained this using the term graduation second
in section 2.2 of 1995 Metrologia 31 431
http://iopscience.iop.org/0026-1394/31/6/002
He points out that the way the IAU has written
I don't think it is correct to say that astronomers are being thrown to the
wolves. The IAU has not taken a stand on this - if it were so simple then the
disagreements that were expressed in the IAU deliberations would not have been
sufficient to prevent a resolution. It is true that some
On Nov 6, 2014, at 8:04 PM, Alex Currant via LEAPSECS leapsecs@leapsecond.com
wrote:
The IAU has not taken a stand on this - if it were so simple then the
disagreements that were expressed in the IAU deliberations would not have
been sufficient to prevent a resolution.
This is not correct.
On Fri, Nov 7, 2014 at 2:24 AM, Dennis Ferguson dennis.c.fergu...@gmail.com
wrote:
In some ways the UTC minute redefinition is even worse than that. A 6
year old
might not know how many seconds are in a hectosecond but would often be
expected to know there are 60 seconds in a minute.
I am sorry but my statement was correct: the IAU has not taken a stand. My
statement was correct because an IAU Working Group is not the IAU, and that IAU
leadership has been explicitly clear about this point. I am sure the demeanor
of everyone in the WG was professional. But I would also
On Fri 2014-11-07T05:19:25 +, Alex Currant via LEAPSECS hath writ:
I am sorry but my statement was correct: �the IAU has not taken a stand.
The Report of the IAU Working Group on UTC was posted via
the IAU Division A website, and then it was disappeared.
It will be interesting to see if it
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