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
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, Nov 7, 2014 at 2:24 AM, Dennis Ferguson 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. Redefining this to be
> otherw
On Nov 6, 2014, at 8:04 PM, Alex Currant via LEAPSECS
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. The IAU UTC working
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 esti
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
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 Ei
On Nov 6, 2014, at 11:24 AM, Dennis Ferguson
wrote:
>>
>> On Nov 6, 2014, at 11:19, Clive D.W. Feather 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 seconds.
>>>
>>> The etymolo
> On Nov 6, 2014, at 11:19, Clive D.W. Feather 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 seconds.
>>
>> The etymology is actually helpful in this case rather than misleading as
>> e
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 [mailto:leapsecs-boun...@lea
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 p
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 que
On Thu, Nov 6, 2014 at 10:37 PM, Poul-Henning Kamp
wrote:
>
> In message 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 navi
Poul-Henning Kamp 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 minuta pr
On Nov 6, 2014, at 5:55 AM, Zefram wrote:
> Warner Losh wrote:
>> On Nov 5, 2014, at 10:54 AM, Zefram 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
On Nov 6, 2014, at 5:09 AM, Zefram 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 equivalent,
On Nov 6, 2014, at 4:40 AM, michael.deckers via LEAPSECS
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 are computing th
On Nov 5, 2014, at 7:57 PM, 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, since it is hard to
> imagine how a lab could get a different offset attempting to realize TAI fro
In message
, 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 somebody told him that the degree between 23°59' and 24°00' had
sixt
On Thu, Nov 6, 2014 at 8:38 PM, Tony Finch 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 radians.
>
.
Bonjour,
Michael Deckers via LEAPSECS 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, not everything is
|>
Warner Losh wrote:
>On Nov 5, 2014, at 10:54 AM, Zefram 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 definitions do you
Zefram 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 2pi/86400
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 defin
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
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 fr
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 de
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, since it is
> hard to imagine how a lab could get a different offset attempting to
> realize TAI from attempting to realize UTC. T
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 produci
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