First, to clarify what I meant by UTC being inaccurate. IMO, UTC is
inaccurate as a measure of Earth rotation. It is precise in atomic
seconds, but it is inaccurate for astronomical purposes. Accuracy is
restored to a significant degree by DUT. It is precise to the degree
that contributing
On 01/13/2011 22:19, Tom Van Baak wrote:
It would appear that making adjustments every 10 days is not
often enough, at least in the US, viz:
http://www.nist.gov/pml/div688/grp50/NISTUTC.cfm
http://www.nist.gov/pml/div688/grp50/nistusno.cfm
Even if we abandon the leap second, we have issues at
I was talking to the IT manager for a town in Connecticut, USA. I asked
if town residents could pay taxes and fees online. He said they could. I
asked how they knew if a deadline had been met and whether late
penalties should be added. He said that the town officials were lenient,
and if the
On 01/14/2011 00:22, Sanjeev Gupta wrote:
On Fri, Jan 14, 2011 at 13:47, Tom Van Baak t...@leapsecond.com
mailto:t...@leapsecond.com wrote:
You really didn't expect 250 diffeent atomic clocks around
the world to all agree at the ns level at all times did you?
tounge-in-cheek
Why
On 01/14/2011 03:29, Tony Finch wrote:
On Thu, 13 Jan 2011, Steve Allen wrote:
Alas, 'tis neither normal nor expected by the APIs and the programmers
who are implementing systems that deal with time.
One of the core abstractions provided by operating systems is some
coherent model of time. And
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
On 2011-01-14 16:26, Warner Losh wrote:
The BIPM collects time and frequency data for the different clocks,
measured against each other. Each clock then has an error in frequency
and time computed. These clocks are then weighted based on assigned
values (based on the time scientists
Continuously adjusting clocks, even atomic clocks, to keep them within
a certain tight tolerance is, in general, not a good pratice. Clocks
will keep better time if left running. Rather, the offset of the
clock from the standard is measured and used as appropriate.
Performance levels of
On 01/14/2011 09:40, Richard Langley wrote:
Continuously adjusting clocks, even atomic clocks, to keep them within
a certain tight tolerance is, in general, not a good pratice. Clocks
will keep better time if left running. Rather, the offset of the
clock from the standard is measured and used
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
In message 3b33e89c51d2de44be2f0c757c656c8809f66...@mail02.stk.com, Finklema
n, Dave writes:
It is ironic that the shift in astrological signs made headlines this
morning while the significance of Earth rotation and orientation
parameters escapes notice.
Nobody ever went broke because
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.
They are not different flavors of time, one is a measurement of
time, the other a
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.
They are not
In message p06240800c9568ccc4ca3@[192.168.1.100], Joe Gwinn writes:
At 3:03 PM -0700 1/14/11, Rob Seaman wrote:
UNIX chose 00:00:00 GMT 1 January 1970 as their epoch simply to be
synchronized with civil time, at least initially.
The initial versions of the operating system, which later became
The process was even more complex while the rate of TAI was
intentionally increased during 1995..1998.
Could somebody say more? Or tell me what to google for?
--
These are my opinions, not necessarily my employer's. I hate spam.
___
On 01/14/2011 20:21, Hal Murray wrote:
The process was even more complex while the rate of TAI was
intentionally increased during 1995..1998.
Could somebody say more? Or tell me what to google for?
http://www.ucolick.org/~sla/leapsecs/dutc.html#TAI
gives the answers.
Warner
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