Professional and amateur astronomers are not the only ones who need good
estimates of UT1.
I've been wondering about this for a bit. Do astronomers and
navigators actually want UT1 or do they want GMST? Since UT1 is
based on a mean sun, which I guess no one actually observs, it would
seem that
M. Warner Losh said:
1500 years ago, no one spoke English. Chances are the people that
deal with this problem in 1000 or 2000 years won't speak any language
recognizable to anybody alive today.
Why not? Greek and Latin, to name two, were spoken that long ago and are
recognisable today.
And
On Mon 2006-01-23T11:08:29 +, David Malone hath writ:
As far as I can see from my 1992 edition of the Explanatory Supplement
to the Astronomical Almanac, UT1 and GMST were (defined?)
the relationship seems to have been changed to ones documented in
(Capitaine et al., 2000, Capitaine et
Clive D.W. Feather scripsit:
Why not? Greek and Latin, to name two, were spoken that long ago and are
recognisable today.
Indeed, and they passed through a far tighter bottleneck than anything
likely today.
Not even the most diligently destructive barbarian can
extirpate the
John Cowan [EMAIL PROTECTED] wrote:
Once we have accomplished the former [changing the basis of civil time],
I don't give a hoot about the latter [hobbling UTC].
Keep UTC if you want.
Then what are you doing here? Why don't you go to your elected
representatives in whatever country you call
On Sat 2006/01/21 10:11:04 PDT, M. Warner Losh wrote
in a message to: LEAPSECS@ROM.USNO.NAVY.MIL
You really should read the archives of this list. We've been over
this in great detail. TAI is specifically contraindicated as a time
I don't think new contributors (or even old ones) should have
On Sat 2006/01/21 15:15:32 PDT, M. Warner Losh wrote
in a message to: LEAPSECS@ROM.USNO.NAVY.MIL
Somewhere around betwee 45,000-80,000 you'll need more than one leap
second a day.
You should recognize this as a reductio ad absurdum argument; at that
time there will be 86401 SI seconds per day -
M. Warner Losh wrote:
UTC works for navigation, but leap seconds pose problems for other
users of time. Stating absolutely that UTC is not broken ignores
these other users.
Those other uses, for whom leap seconds pose a problem, should be
using a time scale that does not have leap seconds.
On 21 Jan 2006 at 10:11, M. Warner Losh wrote:
I maintain that for human activity, there's no need for leap seconds
at all. In each person's lifetime, the accumulated error is on the
order of a few minutes. Over generations, the problems with noon
drifting to 1pm can trivially be solved by
In message: [EMAIL PROTECTED]
Daniel R. Tobias [EMAIL PROTECTED] writes:
: On 21 Jan 2006 at 10:11, M. Warner Losh wrote:
:
: I maintain that for human activity, there's no need for leap seconds
: at all. In each person's lifetime, the accumulated error is on the
: order of a few
On Jan 20, 2006, at 10:17 PM, M. Warner Losh wrote:
Any watch that is smart enough to decode those signals would be
smart enough to add this minor correction as well.
A viable time scale could be constructed from any periodic (or near
periodic) waveform - there's nothing magic about the tick,
On Jan 21, 2006, at 12:03 AM, M. Warner Losh wrote:
WWV and most of the world's time stations broadcast DUT1. I should
have added in my last message that some change in the signal format
would be necessary if the range of DUT1 exceeds 0.9s.
Bearing in mind that the ITU proposal would cease
On 21 Jan 2006 at 15:15, M. Warner Losh wrote:
For some perspective, we've been using UTC for only ~50 years and the
gregorian calendar for only ~1500 years. I'd anticipate that
something would need to be done about the slowing of the day well
before 4300 years have passed.
Actually, that's
On Jan 21, 2006, at 10:11 AM, M. Warner Losh wrote:
Over generations, the problems with noon drifting to 1pm can
trivially be solved by moving the timezones that civilian time uses.
Neither trivial or a solution - quadratic disaster still looms.
Keeping universal time synchronized to an
Rob Seaman scripsit:
Only a minority (small minority, one would think) of
systems currently include any DUT1 correction at all - although these
will perhaps tend to be the most safety-critical applications. [...]
That is, of course, one of the major issues for astronomers - we rely
on UTC
On Fri, Jan 20, 2006 at 03:12:15PM -0500, John Cowan wrote:
Rob Seaman scripsit:
Only a minority (small minority, one would think) of
systems currently include any DUT1 correction at all - although these
will perhaps tend to be the most safety-critical applications. [...]
That is, of
In reply to Rob Seaman, John Cowan wrote:
Seaman: [A]s clock
time diverges further and further from solar time, more systems in
more communities (transportation, GIS, innumerable scientific
disciplines, what have you) would be revealed to need remediation.
Cowan:
Can you spell out some of
In message: [EMAIL PROTECTED]
James Maynard [EMAIL PROTECTED] writes:
: ones position using sight reduction tables. Today a mechanical watch or
: chronometer, or a battery-powered wristwatch, can be set to UTC using
: radio time signals. Then when power fails, the sailor still has a
:
Neal McBurnett scripsit:
To sum it up, PLEASE don't fundamentally change the DEFINITION of UTC,
or you risk whole new kinds of confusion. Hopefully by now the folks
on this list that don't like leap seconds at least have agreed that
any change should be to a new time scale like TI, and
James Maynard scripsit:
Small boats, sea water, and electrical systems don't mix very well. The
damp, salty environment all too often leads to failures of a boat's
electrical system. A prudent sailor should not rely for navigation only
on electrically powered systems like GPS or loran.
Your
M. Warner Losh wrote:
In message: [EMAIL PROTECTED]
James Maynard [EMAIL PROTECTED] writes:
: M. Warner Losh wrote:
: In message: [EMAIL PROTECTED]
: James Maynard [EMAIL PROTECTED] writes:
: : ones position using sight reduction tables. Today a mechanical watch or
:
- Original Message -
From: James Maynard [EMAIL PROTECTED]
To: LEAPSECS@ROM.USNO.NAVY.MIL
Sent: Friday, January 20, 2006 9:33 PM
Subject: Re: [LEAPSECS] Risks of change to UTC
M. Warner Losh wrote:
In message: [EMAIL PROTECTED]
James Maynard [EMAIL PROTECTED] writes:
:
In message: [EMAIL PROTECTED]
James Maynard [EMAIL PROTECTED] writes:
: M. Warner Losh wrote:
:
: : If DUT1 is broadcast, then one can set the time keeping device to UT1
: : by a means similar to setting it to UTC, even if DUT1 exceeds 0.9s
: : with a similar accuacy (or better).
23 matches
Mail list logo
