Re: The real problem with leap seconds

2006-01-13 Thread Michael Deckers
On 2006-01-13, Mark Calabretta wrote: I have two time scales, TAI and UT1, that tick at very slightly different rates. I want to make TAI the basis for civil time keeping but I need to make adjustments occasionally to keep it in step with UT1. How do I do it? The answer provided

Re: The real problem with leap seconds

2006-01-13 Thread Ed Davies
Michael Deckers wrote: I believe I'm now grasping what you mean: the rate of UTC is the same as the rate of TAI (since 1972), that is, the derivative d( UTC )/d( TAI ) = 1. ... This conversation is making something of a meal of a simple point. You can treat UTC as a real in either of

Report of Leap Second Problem with GPS Data

2006-01-13 Thread Richard Langley
FYI. -- Richard Langley Professor of Geodesy and Precision Navigation === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web:

Re: The real problem with leap seconds

2006-01-13 Thread Michael Deckers
On 2006-01-13, Ed Davies wrote: This conversation is making something of a meal of a simple point. You can treat UTC as a real in either of two ways: If you don't count the leap seconds then the good news is that days are all 86 400 seconds long but the bad news is that the real is

Problems with GLONASS Raw Receiver Data at Start of New Year

2006-01-13 Thread Richard Langley
The International GNSS Service (IGS) includes a sub-network of continuously operating GLONASS monitor stations (about 50) including one at the University of New Brunswick (UNB1). At UNB1 we lost C1 (coarse code on L1 frequencies), P1 (precision code on L1), and P2 (precision code on L2)

Re: The real problem with leap seconds

2006-01-13 Thread Ed Davies
Michael Deckers wrote: Sort of like, is it a particle or a wave? :-) At the risk of being misunderstood as sarcastic: if users of UTC were really expected to understand such strange concepts (Schrodinger time) I would plead for the immediate abolishment of UTC. Why cannot UTC

Re: The real problem with leap seconds

2006-01-13 Thread Ed Davies
Markus Kuhn wrote: Ed Davies wrote on 2006-01-13 11:45 UTC: The use of the 23:59:60 notation is described in ISO 8601. Is it also specified in TF.460? It originally comes from ITU-R TF.460, which is a standard for radio time signals. OK, thanks. Ed.

Analog clocks and leap seconds

2006-01-13 Thread Tom Van Baak
Michael Sokolov writes: I cannot make the beautiful analog clock on the tower show 23:59:60. But it's trivial to make it occasionally take 1.1 SI seconds instead of 1 SI second to turn its hands by 1 civil second. Yes, this is one of the awkward features of a leap second (positive leap second,

Re: The real problem with leap seconds

2006-01-13 Thread Rob Seaman
I'm glad to see such active traffic on the list - particularly discussions such as this that are wrestling with fundamental concepts. On 2006-01-13, Mark Calabretta wrote: The point is that UTC is simply a representation of TAI. On Jan 13, 2006, at 4:17 AM, Michael Deckers wrote: I

Re: The real problem with leap seconds

2006-01-13 Thread Rob Seaman
On Jan 13, 2006, at 8:05 AM, Ed Davies wrote: MJD 27123.5 means 12:00:00 on day 27123 if it's not a leap second day, but what does it mean on a day with a positive leap second? 12:00:00.5? And we're back to the point in question. The precise issue is the definition of the concept of a day.

Re: The real problem with leap seconds

2006-01-13 Thread Tim Shepard
We've recently had a question about this on this list which wasn't answered clearly. MJD 27123.5 means 12:00:00 on day 27123 if it's not a leap second day, but what does it mean on a day with a positive leap second? 12:00:00.5? I think it only works if that level of precision doesn't

Re: Analog clocks and leap seconds

2006-01-13 Thread John Hawkinson
Tom Van Baak [EMAIL PROTECTED] wrote on Fri, 13 Jan 2006 at 07:31:50 -0800 in [EMAIL PROTECTED]: But if you were to design an analog clock that was somehow leap second compatible here is my list of possible implementations: ... Please consider a clock with a leap second hand that simply goes

Re: The real problem with leap seconds

2006-01-13 Thread Michael Deckers
On 2006-01-13, Ed Davies wrote: Michael Deckers wrote: . Why cannot UTC be simply taken as the reading of a clock that runs at the same rate as TAI and that is is set back by a second every once in a while? UTC can be taken the way you suggest most

Re: The real problem with leap seconds

2006-01-13 Thread Warner Losh
From: Ed Davies [EMAIL PROTECTED] Markus Kuhn wrote: Ed Davies wrote on 2006-01-13 11:45 UTC: The use of the 23:59:60 notation is described in ISO 8601. Is it also specified in TF.460? It originally comes from ITU-R TF.460, which is a standard for radio time signals. OK, thanks.

Re: The real problem with leap seconds

2006-01-13 Thread William Thompson
I don't know about a canonical list, but one standard document that is used within NASA is CCSDS 301.0-B-3, which is available from the Consultative Committee on Space Data Systems website at http://public.ccsds.org/publications/BlueBooks.aspx This standard references ISO-8601, and is

Re: Monsters from the id

2006-01-13 Thread Tom Van Baak
It should be clear that the gaps and repeats are fictitious, especially if you think of AEST and AEDT as existing beyond the times when they are in legal use. Putting it in practical terms, suppose I have a traffic accident at 0230 on 2006/04/02, what time will the police officer write in

Time standards: RFC3339 and ISO 8601, NTP

2006-01-13 Thread Neal McBurnett
On Fri, Jan 13, 2006 at 11:32:36AM -0700, Warner Losh wrote: Has anybody compiled a canonical list of the standards in this area? This is the first, I think I've seen ISO 8601 mentioned. As usual, the IETF does a much better job than the ITU of making this stuff available to the general public.