On Thu 2003-01-30T00:28:57 -0800, Ken Pizzini hath writ:
Right, but in its way UT1 is king because that is the measure of
earth-position time which is used in the definition of our current
time standard, UTC.
I would go so far as to argue that UT1 is not time, but angle.
UT1 does not measure
John Cowan wrote on 2003-01-30 13:01 UTC:
Markus Kuhn scripsit:
Unix timestamps have always been meant to be an encoding of a
best-effort approximation of UTC.
Unix is in fact older than UTC.
This is getting slightly off-topic, but Unix slowly evolved and was
reimplemented various times
Markus Kuhn scripsit:
It also provides the formula that defines the encoding of UTC into that
integer, leaving no doubt about the exact semantics.
I agree that this is clear, and I continue to believe that it is a regrettable
and unjustified change from existing older practice, not a mere
Steve Allen wrote on 2003-01-30 20:17 UTC:
The specifications for the automatic telescope call for an object to
appear within 10 arcsec of the field center after a slew. This is
congruent with what the telescope engineers can do with the flexure
and hysteresis, but it obviously requires UT1
On Thu 2003-01-30T12:54:09 +, Markus Kuhn hath writ:
VERDIN phase tracking is perhaps a somewhat pathological case.
True, but I know of someone who built a household clock to use it, and
for someone living in a Navy base town during the early years of the
Reagan era that seemed like a
Steve Allen wrote on 2003-01-30 20:58 UTC:
On Thu 2003-01-30T12:54:09 +, Markus Kuhn hath writ:
The UCPTE specification says that the grid phase vectors have to rotate on
long-term average exactly 50 * 60 * 60 * 24 times per UTC day.
Obviously the grid frequency shift after leap seconds
John Cowan said:
Fact 2 is that the old 1980s pre-POSIX Unix manuals talked about GMT and
not UTC. This strongly suggests that the authors were unfamiliar with
both TAI and UTC. The seconds they refer to behave more like UT1
seconds than like TAI/SI seconds, i.e. they are Earth rotation angles
As one of the main people who worked on time related aspects of the
IEEE P1003.1 POSIX standard, I'd like to make a few comments about how
it came to be the way it is now.
First I'd like to tell you about the early consensus on time; before
any of the POSIX time specs were written. I'm not
On Thu 2003-01-30T22:05:51 +, Markus Kuhn hath writ:
But the question arises as to why the spec
can't easily be changed to indicate that it is per TAI day.
As long as UTC is as it is currently, you don't want to do this:
But I think that the further answer is this:
Should it be decided
Thanks to Steve for the reference:
http://danof.obspm.fr/IAU_resolutions/Resol-UAI.htm
I reproduce below a resolution of more specific relevance to this
discussion that was made at that meeting of the International
Astronomical Union. I'm glad the IAU is looking at a wider range of
options
On Fri, Jan 31, 2003 at 12:28:28AM +, [EMAIL PROTECTED] wrote:
I think
the historical fact that people used to treat the earth's rotation
as the ultimate reference for the passage of time is not the most
relevant factor in the
On Thu 2003/01/30 15:39:26 -, Markus Kuhn wrote
in a message to: [EMAIL PROTECTED]
If you make every UTC day 86400 + epsilon(date) days long, then life
gets more difficult for people who broadcast standard frequencies such
as 50. Hz TV sync signals, because now you can't simply say
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