Re: [LEAPSECS] UT1 offset
Hello all: A couple of days ago, I started to draft a response to the question raised but got waylaid. I think others have already address the issue fairly well but here's my reply for the record (a bit long-winded): Earth orientation data are provided in the new(ish) GPS CNAV navigation message structure and is documented in IGS-IS-200 (as already point out). They are only needed by those working in the ECI (Earth-Centred Inertial) frame. That leaves out the majority of GPS users. If you are doing orbit integration to improve the orbits of the GPS satellites you might benefit from this data. But I wonder who in the academic community, for example, is actualy using this information in the CNAV messages. I might enquire of some colleagues. By the way, GPS and the other GNSS are used daily (using mostly IGS archived data) to actually determine very accurate Earth orientation data, which is used by the IERS to create data files for Earth rotation/orientation researchers. I used to be one of them. ;-) 30.3.3.5 Message Type 32 Earth Orientation Parameters (EOP) The earth orientation parameters are provided in Message Type 32. The parameters are defined below, followed by material pertinent to the use of the data. ... 30.3.3.5.1 EOP Content Message Type 32, Figure 30-5, provides SV clock correction parameters (ref. Section 30.3.3.2) and earth orientation parameters. The EOP message provides users with parameters to construct the ECEF and ECI coordinate transformation (a simple transformation method is defined in Section 20.3.3.4.3.3.2). The number of bits, scale factors (LSBs), the range, and the units of all EOP fields of Message Type 32 are given in Table 30-VII. 30.3.3.5.1.1 User Algorithm for Application of the EOP The EOP fields in the Message Type 32 contain the EOP data needed to construct the ECEF-to-ECI coordinate transformation. The user computes the ECEF position of the SV antenna phase center using the equations shown in Table 30-II. The full coordinate transformation for translating to the corresponding ECI SV antenna phase center position may be accomplished in accordance with the computations detailed in Chapter 5 of IERS Technical Note 36: IERS Conventions (2010) and equations for UT1, xp and yp as documented in Table 30-VIII. For UT1, Table 30-VIII documents the relationship between GPS time and UT1 with ΔUTGPS and ΔU̇ TGPS. Users who may need ΔUT1 (UT1-UTC) as detailed in Chapter 5 of IERS Technical Note 36: IERS Conventions (2010) can calculate this parameter from UT1-UTC, or more accurately as (UT1-GPS) + (GPS-UTC), using intermediate quantities (UT1-GPS) and (GPS-UTC) which are produced during calculation of UT1 and UTC. Figure 5.1 on page 73 of that document depicts the computational flow starting from GCRS (Geocentric Celestial Reference System) to ITRS (International Terrestrial Reference System). Ongoing WGS 84 re-adjustment at NGA and incorporating the 2010 IERS Conventions, are expected to bring Earth based coordinate agreement to within 2 cm. In the context of the Conventions, the user may as a matter of convenience choose to implement the transformation computations via either the "Celestial Intermediate Origin (CIO) based approach” or the “Equinox based approach”. The EOPs are used to calculate UT1 (applied in the "Rotation to terrestrial system" process) and the polar motion parameters, xp and yp (applied in the "Rotation for polar motion" process). Details of the calculation are given in Table 30-VIII. -- Richard Langley ------------- | Richard B. Langley E-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca | | Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 | | University of New Brunswick | | Fredericton, N.B., Canada E3B 5A3 | | Fredericton? Where's that? See: http://www.fredericton.ca/ | - From: LEAPSECS on behalf of Tom Van Baak Sent: January 2, 2024 10:44 AM To: Leap Second Discussion List Subject: Re: [LEAPSECS] UT1 offset ✉External message: Use caution. Hi Mike, > the system needs an estimate of current UT1 Can you give some references to your observation? I don't recall seeing UT1 mentioned in the first couple of decades of GPS documentation. The system runs on GPS time, the WGS84 coordinate system, broadcast ephemeris including SV clock corrections. Where does UT1 appear in those? > That estimate is applied internally so the end user does not need to know the > details Right, the user is shielded from many details. But I didn't think even GPS receivers had knowledge of UT1, nor t
Re: [LEAPSECS] speeding up again?
https://www.science.org/content/article/longer-days-brought-you-el-ni-o Also: Investigating the Relationship Between Length of Day and El-Niño Using Wavelet Coherence Method: https://link.springer.com/chapter/10.1007/1345_2022_167 -- Richard Langley - | Richard B. Langley E-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca | | Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 | | University of New Brunswick | | Fredericton, N.B., Canada E3B 5A3 | | Fredericton? Where's that? See: http://www.fredericton.ca/ | - From: LEAPSECS on behalf of Tom Van Baak Sent: June 15, 2023 10:48 PM To: leapsecs@leapsecond.com Subject: Re: [LEAPSECS] speeding up again? ✉External message: Use caution. Steve, > We can probably put a lot of the blame onto El Niño That sounds plausible but I'm suspicious of quick and simple explanations. You work at/for a university, near the coast, yes? Can you ping some of your climatology / oceanography colleagues and get data going back as far as they have it? I think it would be useful to see what the correlation coefficient actually is. Attached is an LOD plot I made a while ago. A random web google link says "The five strongest El Niño events since 1950 were in the winters of 1957-58, 1965-66, 1972-73, 1982-83 and 1997-98". To my eyeball I just don't see that in the historical LOD plot. /tvb On 5/26/2023 9:09 AM, Steve Allen wrote: On Mon 2023-05-22T16:44:30+0200 Tony Finch hath writ: The prospect of a negative leap second is receding. The longer-term projected length of day from Bulletin A has been increasing towards 24h in recent months. We can probably put a lot of the blame onto El Niño -- Steve Allen<mailto:s...@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Inside GNSS published an update of my CGSIC talk
"I'd also note that if GLASNOS can't be fixed by 2035 ..." Interesting slip of the tongue. Glasnos[t] was taken to mean increased openness and transparency in government institutions and activities in the Soviet Union (USSR). Glasnost reflected a commitment of the Gorbachev administration to allowing Soviet citizens to discuss publicly the problems of their system and potential solutions. Of course, GLONASS was meant. But we are reminded that in today's Russia, openness and transparency, not to mention freedom of speech, is a thing of the past. Sorry for being a bit off topic. -- Richard Langley ----- | Richard B. Langley E-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca | | Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142 | | University of New Brunswick | | Fredericton, N.B., Canada E3B 5A3 | | Fredericton? Where's that? See: http://www.fredericton.ca/ | - From: LEAPSECS on behalf of Warner Losh Sent: March 20, 2023 5:18 PM To: Leap Second Discussion List Subject: Re: [LEAPSECS] Inside GNSS published an update of my CGSIC talk ✉External message: Use caution. On Mon, Mar 20, 2023 at 1:37 PM Michael Deckers via LEAPSECS mailto:leapsecs@leapsecond.com>> wrote: On 2023-03-20 07:54, Jürgen Appel via LEAPSECS wrote: > In your Conclusion, you say "the CGPM resolution also stipulates that no > change to current practices can occur before 2035." > > This is not how I read read the CGPM document on the BIPM website: > "The General Conference on Weights and Measures (CGPM), at its 27th meeting > [...] decides that the maximum value for the difference (UT1-UTC) will be > increased in, or before, 2035," > > So in case the negative leap seconds become a real threat, according to my > interpretation is is an option to increase the tolerance value earlier than > 2035 to avoid trying out negative leap seconds a last and first time. > > Can someone confirm my view? You read correctly, the French (official) version has ..."décide que la valeur maximale pour la différence (UT1 - UTC) sera augmentée au plus tard en 2035," which means "in 2035 at the latest". Note also that the definition of UTC as approved by the CGPM never mentions _any_ explict bound for |UT1 - UTC|; it only says that (TAI - UTC) is an integral multiple of 1 s as determined by the IERS. It is the IERS who state that "Coordinated Universal Time (UTC) a measure of time that conforms, within approximately 1 s, to the mean diurnal motion of the Sun and serves as the basis of all civil timekeeping." quoting the IAU "Nomenclature for Fundamental Astronomy (NFA)" found at http://syrte.obspm.fr/iauWGnfa/NFA Glossary.html. This seems to be lenient enough to allow for not scheduling a negative leap second even in the case that the difference (UT1 - UTC) should go a bit below -1 s before 2035. So is "approximately" here to be read in the "astronomer" sense that it's that, give or take an order of magnitude, or some more close reading :) For astronomy, often times things that are approximately the same can vary quite a bit, and that's fine. More seriously even 2s is approximately 1s if there's some kind of effort to keep it from freewheeling to 10s, 100s, or 1000s of seconds. For example, the Gregorian calendar approximates the year over the centuries, but any given year can deviate up to 2 days (worst case) from the idealized solstice dates. I'd also note that if GLASNOS can't be fixed by 2035, then a fallback to a schedule of leap seconds to keep the answer approximately 1s in the long haul could also be on the table. Having it be scheduled, rather than observational, has advantages: everybody gets leap years right, and will for the next few hundred years (maybe with a glitch at 2100 and 2400). A much lower percentage get leap seconds right because leap second knowledge propagates imperfectly, even after all these years of trying (my first anti-leapsecond screeds date back maybe 20 years). So my first choice is always 'none, cope with shifting civil time on the scale of centuries' but my second choice is 'schedule for the long-term average and don't worry about going > 1s' . Warner Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com<mailto:LEAPSECS@leapsecond.com> https://pairlist6.pair.net/mailman/li
Re: [LEAPSECS] GLONASS leap second
I did not monitor what was going on with GLONASS at the time of the leap second. But no NAGUs were issued indicating that any of the satellites had difficulties around the time of the leap second. Also, I've not yet heard of any issues from users. Roscosmos had this to say about the event (in translation): On the night of 30/06/2015 to 01/07/2015, the scale of the correction of UTC. The procedure for correcting the scale of the GLONASS system nominally held whatever that means. ;-) -- Richard On Friday, July 3, 2015, 184, at 10:33 AM, Tom Van Baak wrote: Richard, or Martin, or anyone, What's the latest on how GLONASS handles leap seconds? I remember years ago receivers (or the SV itself) reset their timescale across the leap event -- because they use UTC(SU)+3h (Moscow local time) as their system time and not a leap-less, timezone-free timescale like GPS system time. Multi-GNSS receivers might be able ride through this with some heuristic so the question is more what really happens underneath, or to GLONASS-only receivers these days? Thanks, /tvb (2013) GLONASS TIME AND UTC(SU) http://spacejournal.ohio.edu/issue9/pdf/UsingGLONASS.pdf (2013) GLONASS and Coordinated Universal Time https://itunews.itu.int/En/4275-GLONASS-and-Coordinated-Universal-Time.note.aspx (2008) GLONASS ICD https://www.unavco.org/help/glossary/docs/ICD_GLONASS_5.1_(2008)_en.pdf (2005) Using GLONASS in Combined GNSS Receivers: Current Status http://www.unoosa.org/pdf/icg/2013/icg-8/wgD/D4a.pdf (2001) The leap second: its history and possible future https://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf (1999) GPS and Leap Seconds: Time to Change? http://www2.unb.ca/gge/Resources/gpsworld.november99.pdf (1990) CURRENT GPS/GLONASS TIME REFERENCES AND UTC http://tycho.usno.navy.mil/ptti/1990papers/Vol%2022_06.pdf ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap second festivities?
Was on the front page of two of the New Brunswick dailies this morning, extolling the pros and cons and whyfors of leap seconds. Single malt for me and I'll record CHU but out of the earshot of my wife. She already knows I'm a time nut. ;-) -- Richard On Tuesday, June 30, 2015, 181, at 10:46 AM, Rob Seaman wrote: What are people’s plans for the day? Aside from reading the usual mishmash of bad (and some good) news articles, I’m planning to make a shaker of Margaritas in my rocket ship (http://bit.ly/1HvwlHn) and watch / listen to the music of the time signals with my perplexed but patient family. Trending meme for the day: two instances of the same Doctor Who pun on Peter’s name: Whibberley-Wobbly timey-wimey Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap second festivities?
From: WE SHOULD DROP THE LEAP SECOND BEFORE IT CAUSES REAL DAMAGE http://www.wired.com/2015/06/just-drop-leap-second-unnecessary/ Matsakis advocates the abolition of the leap second, pointing out that we already spend so much our time out of sync with the earth’s rotation. “This is what happens in the summertime,” he says. “We do Daylight Savings.” He may get his wish. In November, members of the International Telecommunications Union—another global time body—are set to discuss the matter. But according to Steve Allen, a programmer with California’s Lick Observatory who closely follows the leap second and other global matters of time, the ITU has been discussing the leap second for years. At the last big meeting, Britain, Canada, and China all moved to keep it alive. Britain’s stance is to be expected. It sees itself as the world’s time keeper. Greenwich Mean Time and all that. If we remove the leap second, the world’s clocks and computers will drop out of sync with GMT, which is based on the sun. That would be sad. But times change. I've heard that this time around, in November, Canada's position will be neutral. -- Richard On Tuesday, June 30, 2015, 181, at 10:46 AM, Rob Seaman wrote: What are people’s plans for the day? Aside from reading the usual mishmash of bad (and some good) news articles, I’m planning to make a shaker of Margaritas in my rocket ship (http://bit.ly/1HvwlHn) and watch / listen to the music of the time signals with my perplexed but patient family. Trending meme for the day: two instances of the same Doctor Who pun on Peter’s name: Whibberley-Wobbly timey-wimey Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
[LEAPSECS] Atomic time: 60 years of the ultra-precise atomic clock
http://eandt.theiet.org/magazine/2015/05/60-years-of-atomic-time.cfm - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap in june
There's a lot of crap being written about the upcoming leap second in the popular press -- the usual end-of-the-world stuff. A slightly refreshing article here: http://www.wired.com/2015/01/torvalds_leapsecond/ -- Richard Langley On Friday, January 9, 2015, 9, at 9:24 AM, Tom Van Baak wrote: They were wise enough to ask Markus to write it; a nice balance between popular and technical. They were kind enough to ask permission to use a cesium clock leap second photo from my web site. Not something you see every day indeed! https://theconversation.com/an-extra-second-on-the-clock-why-moving-from-astronomic-to-atomic-time-is-a-tricky-business-35970 Markus -- your LOD plot ends in 2011? /tvb ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap in june
The secular change in the rotation of the Earth as related to the motion of the Moon had been detected by 1695 by Edmond Halley. Suggested explanation given by Emanuel Kant in 1754. Will send the Harold Spencer Jones paper on this later today. The smaller, atmosphere-related fluctuations were discovered in the 1930s (I think) using pendulum clocks. -- Richard Langley On Friday, January 9, 2015, 9, at 3:23 PM, Pierpaolo Bernardi wrote: Markus Kuhn writes: The varying length of the day has been known for centuries but only became a practical concern (outside astronomy) with the invention of atomic clocks in the 1950s. Is this true? I though it was discovered only in the 20th century? From the context he refers to mean solar day, I understand. On Fri, Jan 9, 2015 at 2:24 PM, Tom Van Baak t...@leapsecond.com wrote: They were wise enough to ask Markus to write it; a nice balance between popular and technical. They were kind enough to ask permission to use a cesium clock leap second photo from my web site. Not something you see every day indeed! https://theconversation.com/an-extra-second-on-the-clock-why-moving-from-astronomic-to-atomic-time-is-a-tricky-business-35970 Markus -- your LOD plot ends in 2011? /tvb ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap in june
Not sure I am permitted to distribute the paper through this list. The following includes a link to the JSTOR archive: The Secular Increase in the Length of the Day Harold Spencer Jones Proceedings of the American Philosophical Society Vol. 99, No. 4 (Aug. 30, 1955), pp. 195-199 Published by: American Philosophical Society Stable URL: http://www.jstor.org/stable/3143697 Page Count: 5 -- Richard Langley On Friday, January 9, 2015, 9, at 3:23 PM, Pierpaolo Bernardi wrote: Markus Kuhn writes: The varying length of the day has been known for centuries but only became a practical concern (outside astronomy) with the invention of atomic clocks in the 1950s. Is this true? I though it was discovered only in the 20th century? From the context he refers to mean solar day, I understand. On Fri, Jan 9, 2015 at 2:24 PM, Tom Van Baak t...@leapsecond.com wrote: They were wise enough to ask Markus to write it; a nice balance between popular and technical. They were kind enough to ask permission to use a cesium clock leap second photo from my web site. Not something you see every day indeed! https://theconversation.com/an-extra-second-on-the-clock-why-moving-from-astronomic-to-atomic-time-is-a-tricky-business-35970 Markus -- your LOD plot ends in 2011? /tvb ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
[LEAPSECS] Fwd: Bulletin C number 49
In case anyone didn't get this. Six month's warning. -- Richard Langley Begin forwarded message: From: IERS EOP Product Center services.i...@obspm.fr Subject: Bulletin C number 49 Date: January 5, 2015 at 9:25:49 AM AST To: bulc.i...@obspm.fr Reply-To: IERS EOP Product Center services.i...@obspm.fr INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE DE L'IERS OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 e-mail: services.i...@obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 5 January 2015 Bulletin C 49 To authorities responsible for the measurement and distribution of time UTC TIME STEP on the 1st of July 2015 A positive leap second will be introduced at the end of June 2015. The sequence of dates of the UTC second markers will be: 2015 June 30, 23h 59m 59s 2015 June 30, 23h 59m 60s 2015 July 1, 0h 0m 0s The difference between UTC and the International Atomic Time TAI is: from 2012 July 1,0h UTC, to 2015 July 1 0h UTC : UTC-TAI = - 35s from 2015 July 1,0h UTC, until further notice: UTC-TAI = - 36s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC or to confirm that there will be no time step at the next possible date. Daniel Gambis Head Earth Orientation Center of IERS Observatoire de Paris, France - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
[LEAPSECS] New Clock May End Time As We Know It
As a break from the polemics of leap seconds, here is an interesting item recently broadcast by NPR: http://news.mpbn.net/post/new-clock-may-end-time-we-know-it - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] When did computer timekeeping get good enough for leap seconds to matter?
Does anyone know if the NERC experiment (see below) happened or is still underway? -- Richard Langley From Wikipedia: Regulation of power system frequency for timekeeping accuracy was not commonplace until after 1926 and the invention of the electric clock driven by a synchronous motor. Today network operators regulate the daily average frequency so that clocks stay within a few seconds of correct time. In practice the nominal frequency is raised or lowered by a specific percentage to maintain synchronization. Over the course of a day, the average frequency is maintained at the nominal value within a few hundred parts per million.[17] In the synchronous grid of Continental Europe, the deviation between network phase time and UTC (based on International Atomic Time) is calculated at 08:00 each day in a control center inSwitzerland. The target frequency is then adjusted by up to ±0.01 Hz (±0.02%) from 50 Hz as needed, to ensure a long-term frequency average of exactly 50 Hz × 60 sec × 60 min × 24 hours = 4,320,000 cycles per day.[18] In North America, whenever the error exceeds 10 seconds for the east, 3 seconds for Texas, or 2 seconds for the west, a correction of ±0.02 Hz (0.033%) is applied. Time error corrections start and end either on the hour or on the half hour.[19][20] Real-time frequency meters for power generation in the United Kingdom are available online - an official National Grid one, and an unofficial one maintained by Dynamic Demand.[21][22] Real-time frequency data of the synchronous grid of Continental Europe is available at mainsfrequency.com. The Frequency Monitoring Network (FNET) at the University of Tennessee measures the frequency of the interconnections within the North American power grid, as well as in several other parts of the world. These measurements are displayed on the FNET website. Smaller power systems may not maintain frequency with the same degree of accuracy. In 2011, The North American Electric Reliability Corporation (NERC) discussed a proposed experiment that would relax frequency regulation requirements for electrical grids[23] which would reduce the long-term accuracy of clocks and other devices that use the 60 Hz grid frequency as a time base. And spoofing the power grid: http://gpsworld.com/wirelessinfrastructuregoing-against-time-13278/ On Thursday, January 9, 2014,9, at 12:00 PM, Poul-Henning Kamp wrote: In message 20140109110353.35874406...@ip-64-139-1-69.sjc.megapath.net, Hal Mu rray writes: The IBM 360 systems starting in 1964 used the power line frequency. (A location in low memory got bumped at 300 counts per second. 5 per cycle on 60 Hz and 6 per cycle on 50 Hz.) I wonder how much the power timekeeping wandered back then relative to today. It used to be pretty good, because people used synchronous motors to drive clocks so the power companies tried to keep the long-term frequency correct. In Denmark they usually lost a couple of seconds during the day and gained them back during the night, similarly they lost half a minute over winter and gained it back over summer. After deregulation nobody gets paid to keep the long term frequency, so mains is no good, actually down-right bad, for timekeeping anymore. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://gge.unb.ca/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Fwd: Google Alert - leap second
The International Laser Ranging Service had problems with the leap second last time around. -- Richard Langley Begin forwarded message: From: Google Alerts googlealerts-nore...@google.com Date: January 27, 2013 11:27:47 PM AST To: l...@unb.ca Subject: Google Alert - leap second Web 1 new result for leap second leap second 2012 generalg The June 30July 1 2012 leap second caused some confusion and concern among ... 1 Many stations have hardware that adds the leap second at the right epoch ... ilrs.gsfc.nasa.gov/docs/2012/leapsecond_2012.pdf Tip: Use site restrict in your query to search within a site (site:nytimes.com or site:.edu). Learn more. Delete this alert. Create another alert. Manage your alerts. - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Longer horizon
Found a recording of the 7 pips on You Tube as witnessed at Bush House (now vacated): http://www.youtube.com/watch?v=FTnMLiOqNKk And other You Tube leap second videos: http://www.youtube.com/watch?v=1scvSm3Em3U http://www.youtube.com/watch?v=xfhHPaZb8MI http://www.youtube.com/watch?v=RyPZldmAAG8 (Interesting one.) -- Richard On 11-Jul-12, at 8:38 AM, Peter Vince wrote: Hi Richard, Yes, BBC Radio 4 Long Wave on 198 KHz certainly did. David Malone in Ireland grabbed the LF spectrum and sent a message to the list at 13:25 (British Summer Time) on the 1st of July - his spectrogram at http://www.maths.tcd.ie/~dwmalone/time/leap2012/spectrogram.png clearly shows the six short and seventh longer pips. Speaking to my colleague in Broadcasting House who used to be their Time Lord, they have a new system which is completely automatic, and designed to correctly handle leap-seconds - and it seems to have worked - yippee! Peter On 11 July 2012 12:27, Richard B. Langley l...@unb.ca wrote: Peter: Did any BBC radio station transmit the 7-pip Greenwich Time Signal for the leap second? I did check the iPlayer repeats from BBC Radios 1 through 5 but it appears that these stations, at least via iPlayer, didn't use it. Unlike for the 2008 leap second when Radio 5 made a big deal about it. -- Richard Langley ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Longer horizon
Peter: Did any BBC radio station transmit the 7-pip Greenwich Time Signal for the leap second? I did check the iPlayer repeats from BBC Radios 1 through 5 but it appears that these stations, at least via iPlayer, didn't use it. Unlike for the 2008 leap second when Radio 5 made a big deal about it. -- Richard Langley On 11-Jul-12, at 6:27 AM, Peter Vince wrote: On 11 July 2012 02:42, Michael Spacefalcon msoko...@ivan.harhan.org wrote: Of course. However, this issue would only exist if the external time input is an ASCII string or struct in HH:MM:SS format, and I have yet to see a system that uses such formats for time interchange. All systems that I'm familiar with use time-as-a-real-number formats instead: JD, MJD, time_t, NTP, etc. SF We use a twenty-year-old system that does just that - outputs an ASCII string once a second at 300 baud on a good old-fashioned serial line. Admittedly this was not designed for computer use, but for hardware that will then drive either physical clocks, or produce SMPTE/EBU time code (as used by radio and television broadcasting). Peter (BBC, London) ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Leap Second and GNSS Probems
It appears that Roscosmos, the Russian Space Agency, had difficulties in monitoring the GLONASS satellites in the couple of hours preceding the leap second according to this chart that appeared on one of its websites: inline: getImageFromDB.gif The time scale is in Moscow Time, which is UTC + 4 hours. Roscosmos uses a global network of monitoring sites (including one at UNB) to check the status of the satellites. It is not clear if the monitoring problem was due to Internet communications problems or the satellites themselves. My guess is Internet communications problems and I guess we can't rule out possible NTP problems. -- Richard On 1-Jul-12, at 11:24 PM, Richard B. Langley wrote: A u-blox 6 GPS Engine did not play nice with the leap second. This new engine is GPS/SBAS/QZSS/GLONASS compatible but it only runs in either GPS/SBAS/QZSS mode or GLONASS mode. I was running it under GLONASS mode for the leap second check and recording its NMEA messages. Just before the leap second, it was tracking 9 satellites. At the leap second it reset itself. I don't know if this was caused by an error associated with the leap second or the receiver was programmed to do this. At second 0 of 1 July, it ceased positioning and did not know the time (at least no information was in the $GLZDA NMEA message). At 00:00:40.48 seconds, it once again knew UTC, and by 00:02:39.00, it was tracking enough GLONASS satellites (4) to report position information again. Extracted $GLGGA and $GLZDA messages from before and after the leap second are in the appended file. I'll be contacting u-blox to report the behaviour. Note that when I was monitoring a previous leap second with a GPS- only u-blox receiver, it sailed through the leap second with no problem: $GPZDA,235955.00,31,12,2005,00,00*6D $GPZDA,235956.00,31,12,2005,00,00*6E $GPZDA,235957.00,31,12,2005,00,00*6F $GPZDA,235958.00,31,12,2005,00,00*60 $GPZDA,235959.00,31,12,2005,00,00*61 $GPZDA,235960.00,31,12,2005,00,00*6B $GPZDA,00.00,01,01,2006,00,00*62 $GPZDA,01.00,01,01,2006,00,00*63 $GPZDA,02.00,01,01,2006,00,00*60 $GPZDA,03.00,01,01,2006,00,00*61 $GPZDA,04.00,01,01,2006,00,00*66 $GPZDA,05.00,01,01,2006,00,00*67 We may have had trouble tracking GLONASS satellites with some of the continuously operating GNSS receivers operating at UNB and the Russian Space Agency may have had trouble monitoring the GLONASS satellites. I'll report on these anomalies later. -- Richard - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - output.txt___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Leap Second and GNSS Probems
A u-blox 6 GPS Engine did not play nice with the leap second. This new engine is GPS/SBAS/QZSS/GLONASS compatible but it only runs in either GPS/SBAS/QZSS mode or GLONASS mode. I was running it under GLONASS mode for the leap second check and recording its NMEA messages. Just before the leap second, it was tracking 9 satellites. At the leap second it reset itself. I don't know if this was caused by an error associated with the leap second or the receiver was programmed to do this. At second 0 of 1 July, it ceased positioning and did not know the time (at least no information was in the $GLZDA NMEA message). At 00:00:40.48 seconds, it once again knew UTC, and by 00:02:39.00, it was tracking enough GLONASS satellites (4) to report position information again. Extracted $GLGGA and $GLZDA messages from before and after the leap second are in the appended file. I'll be contacting u-blox to report the behaviour. Note that when I was monitoring a previous leap second with a GPS-only u-blox receiver, it sailed through the leap second with no problem: $GPZDA,235955.00,31,12,2005,00,00*6D $GPZDA,235956.00,31,12,2005,00,00*6E $GPZDA,235957.00,31,12,2005,00,00*6F $GPZDA,235958.00,31,12,2005,00,00*60 $GPZDA,235959.00,31,12,2005,00,00*61 $GPZDA,235960.00,31,12,2005,00,00*6B $GPZDA,00.00,01,01,2006,00,00*62 $GPZDA,01.00,01,01,2006,00,00*63 $GPZDA,02.00,01,01,2006,00,00*60 $GPZDA,03.00,01,01,2006,00,00*61 $GPZDA,04.00,01,01,2006,00,00*66 $GPZDA,05.00,01,01,2006,00,00*67 We may have had trouble tracking GLONASS satellites with some of the continuously operating GNSS receivers operating at UNB and the Russian Space Agency may have had trouble monitoring the GLONASS satellites. I'll report on these anomalies later. -- Richard - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - $GLGGA,235950.00,4553.09000,N,06645.01809,W,1,09,0.82,85.8,M,-26.1,M,,*4B $GLZDA,235950.00,30,06,2012,00,00*76 $GLGGA,235951.00,4553.08997,N,06645.01810,W,1,09,0.82,85.6,M,-26.1,M,,*4A $GLZDA,235951.00,30,06,2012,00,00*77 $GLGGA,235952.00,4553.08990,N,06645.01809,W,1,09,0.95,85.3,M,-26.1,M,,*45 $GLZDA,235952.00,30,06,2012,00,00*74 $GLGGA,235953.00,4553.08990,N,06645.01806,W,1,09,0.82,85.3,M,-26.1,M,,*4D $GLZDA,235953.00,30,06,2012,00,00*75 $GLGGA,235954.00,4553.08983,N,06645.01803,W,1,09,0.82,85.2,M,-26.1,M,,*4C $GLZDA,235954.00,30,06,2012,00,00*72 $GLGGA,235955.00,4553.08981,N,06645.01803,W,1,09,0.82,85.0,M,-26.1,M,,*4D $GLZDA,235955.00,30,06,2012,00,00*73 $GLGGA,235956.00,4553.08976,N,06645.01797,W,1,09,0.82,84.6,M,-26.1,M,,*43 $GLZDA,235956.00,30,06,2012,00,00*70 $GLGGA,235957.00,4553.08972,N,06645.01789,W,1,09,0.82,84.2,M,-26.1,M,,*4D $GLZDA,235957.00,30,06,2012,00,00*71 $GLGGA,235958.00,4553.08968,N,06645.01785,W,1,09,0.82,84.0,M,-26.1,M,,*47 $GLZDA,235958.00,30,06,2012,00,00*7E $GLGGA,235959.00,4553.08967,N,06645.01785,W,1,09,0.82,83.7,M,-26.1,M,,*49 $GLZDA,235959.00,30,06,2012,00,00*7F $GLTXT,01,01,02,Resetting GPS*74 $GLGGA,00.00,4553.08966,N,06645.01789,W,1,09,0.82,83.5,M,-26.1,M,,*47 $GLZDA,00.00,01,07,2012,00,00*7D $GLTXT,01,01,00,RF rd pll*21 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA,00,00*54 $GLGGA,,0,00,99.99,,*54 $GLZDA
Re: [LEAPSECS] Recording GPS leap-second
Having the sampled live RF for playback into an arbitrary GPS receiver is a good idea. See my latest GPS World Innovation column for a cost- effective approach using a USRP: http://www.nxtbook.com/nxtbooks/questex/gps0512/ Also, many GPS simulators already have the capability of simulating the leap second for testing receivers ahead of the actual event. There are many monitoring network GPS (and GPS/GLONASS/whatever) receivers of different makes/models/vintages operating continuously, some with data rates as high as 1 Hz or more, that can be checked after the fact for correct operation through the leap second. A u-blox GPS receiver handled the leap second correctly, as evidenced by the NMEA 0183 GPZDA message, during the leap second event of 31 December 2005: http://www.mail-archive.com/leapsecs@rom.usno.navy.mil/msg00903.html -- Richard Langley On 7-May-12, at 4:23 PM, Poul-Henning Kamp wrote: In message 20120507191612.0e6ad73...@walton.maths.tcd.ie, David Malone writes : Are anybody are working on making a spectrum recording of GPS signals around the leapsecond, for use as test-stimuli for testing leap- second handling ? I suspect that a USRP should be able to do the job ? If you have the right front end, I guess it would be possible. Would you just capture a slice around the L1 and L2 frequencies, or try to capture a big chunk of the band? (I guess a few MHz around L1 would probably be enough to be useful.) I have access to a spectrum analyser that works in the band, but its memory is probably too My idea would be at least two hours of L1, suitable to playback later on... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] ITU-R video of RA session
Nicely produced video! On 25-Jan-12, at 7:16 PM, Steve Allen wrote: Rob Seaman found this http://www.youtube.com/watch?v=C-2UqYW9SEs -- Steve Allen s...@ucolick.orgWGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165Lat +36.99855 1156 High StreetVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Leap seconds decision deferred until 2015
Some of the news reports were in error. Canada did not switch sides. Here is a quote from one of Canada's delegates: We can confirm [that] Canada's position at the just concluded RA was opposition to the elimination of the leap second. It is a position we have consistently held at previous ITU surveys. In fact, at the RA, Canada contributed significantly to rallying support for either maintaining the status quo or as a minimum postponing the decision. In the end, support and opposition to the proposed change were about even. I have learned that an agenda item for WRC-15 is being drafted to look at the issue again after further studies at the ITU that will explore a variety of options to providing a universal continuous time standard. -- Richard Langley On 19-Jan-12, at 5:07 PM, Richard B. Langley wrote: It seems Canada switched sides! No mention of China's stand in the article. -- Richard On 19-Jan-12, at 2:51 PM, Daniel R. Tobias wrote: On Thu, January 19, 2012 9:03 am, Tony Finch wrote: http://www.bbc.co.uk/news/science-environment-16625614 I knew it... it's enough of a hot button issue among the handful of people who care about it that nobody wants to commit to actually taking any action, so it will just keep bouncing around between study committees indefinitely. Maybe 100 years from now they'll still be debating it. That's what happens when you've got something that polarizes the interested parties sharply, with one subset strongly favoring change, another subset strongly favoring the status quo, and the vast masses outside these groups not particularly caring one way or the other, so that there will never be enough massive outside pressure to force the governing bodies to take action instead of calling for yet another committee. It's not like this is an issue that will lead to people marching on the capitol, rallying under the Washington Monument to hear a charismatic speaker saying he has a dream of no more leap seconds (or of leap seconds forever), or holding tea parties or occupation encampments to press for one side or the other on this issue. These sorts of mass movements can sometimes force action when the politicians would rather just keep batting the hot potatoes around, but they're not going to develop here. -- Dan Dan's Web Tips: http://webtips.dan.info/ Dan's Mail Format Site: http://mailformat.dan.info/ Dan's Domain Name Site: http://domains.dan.info/ ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Front page of the New York Times
Not so fuzzy here: http://www.nytimes.com/2012/01/19/science/to-keep-or-kill-lowly-leap-second-focus-of-world-debate.html?_r=1 On 19-Jan-12, at 10:12 AM, Rob Seaman wrote: http://www.nytimes.com/images/2012/01/19/nytfrontpage/scan.jpg (below the fold) ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Fwd: Leap Second
!!! -- Richard Begin forwarded message: From: Bertram Arbesser-Rastburg bert...@tec-ee.esa.int Date: January 19, 2012 12:38:05 PM AST Subject: Leap Second Dear colleagues, just to let you know that the decision for abolishing the leap second here at the ITU Radiocommunication Assembly has in the end not been made. best regards, Bertram === Bertram Arbesser-Rastburg Chairman, ITU-R SG3 Tel: +31-71-565-4541 Fax: +31-71-565-4999 E-M: bertram.arbesser-rastb...@ties.itu.int === - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Godot as Waldo
Rob might only be one of those pesky astronomers but he is certainly a well-rounded one. ;-) Someone after my own heart. -- Richard On 19-Jan-12, at 3:22 PM, Rob Seaman wrote: Richard B. Langley shared: Dear colleagues, just to let you know that the decision for abolishing the leap second here at the ITU Radiocommunication Assembly has in the end not been made. VLADIMIR: That passed the time. ESTRAGON: It would have passed in any case. VLADIMIR: Yes, but not so rapidly. ESTRAGON: What do we do now? VLADIMIR: I don't know. Godot last made an appearance in LEAPSECS in April 2006. Give us long enough and we'll finish Act 1. Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Leap seconds decision deferred until 2015
It seems Canada switched sides! No mention of China's stand in the article. -- Richard On 19-Jan-12, at 2:51 PM, Daniel R. Tobias wrote: On Thu, January 19, 2012 9:03 am, Tony Finch wrote: http://www.bbc.co.uk/news/science-environment-16625614 I knew it... it's enough of a hot button issue among the handful of people who care about it that nobody wants to commit to actually taking any action, so it will just keep bouncing around between study committees indefinitely. Maybe 100 years from now they'll still be debating it. That's what happens when you've got something that polarizes the interested parties sharply, with one subset strongly favoring change, another subset strongly favoring the status quo, and the vast masses outside these groups not particularly caring one way or the other, so that there will never be enough massive outside pressure to force the governing bodies to take action instead of calling for yet another committee. It's not like this is an issue that will lead to people marching on the capitol, rallying under the Washington Monument to hear a charismatic speaker saying he has a dream of no more leap seconds (or of leap seconds forever), or holding tea parties or occupation encampments to press for one side or the other on this issue. These sorts of mass movements can sometimes force action when the politicians would rather just keep batting the hot potatoes around, but they're not going to develop here. -- Dan Dan's Web Tips: http://webtips.dan.info/ Dan's Mail Format Site: http://mailformat.dan.info/ Dan's Domain Name Site: http://domains.dan.info/ ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] China
Didn't I read on the list that China had reportedly changed its mind on the proposal and was now in favour of it? But look here: http://eu2.mofcom.gov.cn/aarticle/chinanews/201201/20120107917326.html -- Richard Langley - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Straw men
What a great and thorough catalogue of the various time systems! -- Richard Langley For the true complexity of the situation, see: http://ucolick.org/~sla/leapsecs/timescales.html Rob Seaman National Optical Astronomy Observatory ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Nov 8 statement?
The additional small, albeit increasing, offset that will result from the abolition of leap seconds will remain insignificant compared to the already existing annual variations in local solar time on the Greenwich meridian. These variations, which amount to plus and minus about sixteen minutes, are due to the orbit of the Earth around the Sun being an ellipse rather than a circle and to it being inclined with respect to the Equator. In addition, there exists the range of local solar times across the UK from East to West which amount to some thirty minutes. What has local solar time got to do with anything? Simply another attempted dig by the French on the English? Plus ça change, plus c'est la même chose. ;-) -- Richard Langley On 12-Nov-11, at 12:11 AM, Dennis Ferguson wrote: On 11 Nov, 2011, at 20:21 , Steve Allen wrote: according to http://www.edmontonjournal.com/news/canada/Time+move+Canada+resists+change+atomic+timekeeping/5698405/story.html and many other syndication points for that article there was a Nov 8 statement from Quinn and Arias. Can anyone point to that statement? I think it is this one: http://www.bipm.org/utils/en/pdf/Press_Release_UTC_21st_century.pdf Dennis Ferguson ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] UK clocks change trial being considered
The government is considering moving the UK's clocks forward by an hour for a three-year trial period. More: http://www.bbc.co.uk/news/uk-politics-15490249 - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Leap smear
Full CNAV messages are not being broadcast yet since the current version of the ground control system doesn't support them. A few partial test frames have been transmitted by the first Block IIF satellite. The current NAV messages provide the quasi-Keplerian orbit parameter values for computing satellite coordinates in the WGS 84 ECEF frame. In deriving the orbit parameters, the ground control system operators take into account Earth orientation, including UT1 and polar motion, so that the user doesn't have to. -- Richard Langley On 30-Sep-11, at 5:59 AM, Keith Winstein wrote: On Fri, 30 Sep 2011, mike cook wrote: Le 30/09/2011 09:13, Keith Winstein a écrit : DUT1 gets 31 bits, including the sign, and is in units of 2^(-24) second. They also give a rate of change so it can be approximated to first order by the receiver. Have you got a reference for this Keith? The only info I could find is from Page 18 sub-frame 4 where the GPS-UTC delta is defined maybe the doc was incomplete . And as a bonus, do you know of any receivers which report it? Hi Mike, The 31-bit DUT1 is actually part of the new GPS CNAV navigation message on L2. See IS-GPS-200E table 30-VIII. I'm not sure if they have actually started transmitting it yet. The traditional GPS navigation message also sends ephemeris parameters to convert from ECI of the satellite ephemerides to ECEF, but I do not think DUT1 can necessarily be derived from these, since each ephemeris seems to be transmitted in a different ECI frame. -Keith___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] preprint about timekeeping for neutrino experiment
Commercial civil dual-frequency receivers exist that do not need to know the Y-code and that provide both L1 and L2 measurements and thus removal of almost all of the ionospheric effect. Scan the GPS World website for up-to-date information on GPS and GPS receivers. -- Richard Langley On 30-Sep-11, at 1:08 PM, Ian Batten wrote: On 30 Sep 2011, at 1532, Peter Vince wrote: If they were using stand-alone caesium clocks, then yes - gravity and altitude would make big difference. But they locked their clocks to a single common-view GPS satellite - surely, then, they were both ticking at the same rate, and in sync? If you don't have access to the encrypted L2 frequency, what is the lower bound on clock precision for two separated stations observing some common-view satellites? I would have thought that propagation in the ionosphere would introduce enough uncertainty to make 60ns precision unlikely. It's difficult for the non-specialist to know which errors were reduced by the removal of SA and which errors are inherent to the technology, but one paper I found [1] says that use of the ionospheric model that is transmitted on L1 isn't anything like perfect: Using the broadcast model under normal conditions removes about half of the error (Fees and Stephens 1987) leaving a residual error of around 60-90 nanoseconds during the day and 10 to 20 nanoseconds at night (Knight and Rhoades 1987). I presume that some of these errors can be corrected if you know your location accurately, but what is the real state of the art? ian [1] Dana, P. H. Global Positioning System (GPS) time dissemination for real-time applications. Real-Time Systems 12, 9-40 (1997). ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Britain?s Speaking Clock turns 75: People still dial for the time
http://news.nationalpost.com/2011/07/26/britains-speaking-clock-turns-75-people-still-dial-for-the-time/ - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Fwd: Bulletin C number 42
See comment about cessation of leap seconds and questionnaire towards the end of the item. -- Richard Langley From: IERS EOP Product Center services.i...@obspm.fr Date: 2011•07•08 10:04:45 AM ADT To: bulc.i...@obspm.fr Subject: Bulletin C number 42 INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 Internet : services.i...@obspm.fr Paris, 8 July 2011 Bulletin C 42 To authorities responsible for the measurement and distribution of time INFORMATION ON UTC - TAI NO positive leap second will be introduced at the end of December 2011. The difference between Coordinated Universal Time UTC and the International Atomic Time TAI is : from 2009 January 1, 0h UTC, until further notice : UTC-TAI = -34 s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next possible date. Daniel GAMBIS Director Earth Orientation Center of IERS Observatoire de Paris, France IMPORTANT: After years of discussions, a proposal to fundamentally redefine UTC will come to a conclusive vote in January 2012 at the ITU-R in Geneva. This proposal would halt the intercalary adjustments known as leap seconds that maintain UTC as a form of Universal Time. The Earth Orientation Center of the IERS organizes a survey online with the objective to find out the strength of opinion for maintaining or changing the present system. Link to the questionnaire: http://hpiers.obspm.fr/eop-pc/index.php?index=questionnaire Your response is appreciated before 30 August 2011 __ - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http:// www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Far past and far future
According to Google Scholar, there have been 79 citations of that paper. Likely, the true number of citations is higher. A more recent paper that might be of interest is Lunar Core and Mantle. What Does LLR See? http://cddis.gsfc.nasa.gov/lw16/docs/papers/sci_1_Williams_p.pdf Although I was involved in LLR data analysis as a postdoctoral fellow at MIT between 1979 and 1981, I concentrated on the intra-annual variations in the length of day (and their association with changes in atmospheric angular momentum) rather than the decadal and longer variations. That work was written up in Nature. http://www.nature.com/nature/journal/v294/n5843/abs/294730a0.html Oh, to be a postdoc again (except for the low rate of pay)! -- Richard Quoting Rob Seaman sea...@noao.edu: On May 24, 2011, at 3:58 PM, Steve Allen wrote: On Tue 2011-05-24T23:01:35 +0100, Clive D.W. Feather hath writ: What was the length of the day in the time of the dinosaurs? If there's a better reference than Williams somebody please say so. http://www.agu.org/pubs/crossref/2000/1999RG900016.shtml The paper itself is available from: http://www.eos.ubc.ca/~mjelline/453website/eosc453/E_prints/1999RG900016.pdf There are a large number of references that would be worth following up. It would certainly be good to know what's been going on over the past dozen years while this contingent leap second discussion has occurred. Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Crunching Bulletin B numbers (POSIX time)
Quoting Warner Losh i...@bsdimp.com: On 02/23/2011 05:57, Richard B. Langley wrote: For those who might not be aware. Loran-C in North America is dead. It might be resurrected as eLoran or some other LF service in the future: http://www.ursanav.com/sites/default/themes/danland/images/buzz/pdfs/LF-Solutions-for-APNT-ION2011.pdf Well, eLoran was implemented in the North American chain a couple of years before they started to shut it off. Given that the stations have been decommissioned and the towers blown up in at least some places, I doubt it will ever resurrect. The decision to terminate Loran-C in North America, leaving GPS without an effective backup there, was extensively covered in GPS World. eLoran was initiated but not completed. I had an article in my column about GPS plus eLoran before Loran-C got the chop: http://www.gpsworld.com/transportation/road/innovation-gps-loran-c-6550. -- Richard But the requirements of that system, and how they interacted with other requirements when coupled with inflexible military bureaucracy shows that there's a wide diversity of requirements for some problem domains that you don't run into with a server in a computing center. Warner -- Richard Quoting Ian Batten i...@batten.eu.org: Nope. tried that when getting the spec approved. Approximate times weren't allowed. UTC times were required. There was no way to indicate approximate time in the user interfaces present (how do you blink a 5071A anyway :). The other systems that interfaced to ours had a fixed format, and required UTC and not approximate UTC for a while and then a possible jump in time to actual UTC. Well, if the use-case is navigation (Loran, military) then UTC sans leap seconds isn't much use to you anyway, so the solution of dropping them would take your requirement with it, and you'd seen something closer to UT1. And of course, requirements are simply line items on an invoice, and if deriving immediate UTC costs 10X rather than X, the customer has to make a decision on whether they're prepared to pay for it. Just saying my customer demands X and therefore the rest of you need to enable X isn't realistic. ian ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3 | |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs - | Richard B. LangleyE-mail: l...@unb.ca | | Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ | | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 | | University of New Brunswick Fax: +1 506 453-4943 | | Fredericton, N.B., Canada E3B 5A3| |Fredericton? Where's that? See: http://www.fredericton.ca/ | - ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] LEAPSECS Digest, Vol 51, Issue 22
Those wishing to bone up on geodesy and coordinate systems, especially those used in the U.K., may wish to read: http://www.ordnancesurvey.co.uk/oswebsite/gps/docs/A_Guide_to_Coordinate_Systems_in_Great_Britain.pdf -- Richard Quoting Ian Batten i...@batten.eu.org: On 7 Feb 2011, at 17:21, Finkleman, Dave wrote: I finally get a chance to look like I might know something. Neiher Gravity nor the Geoid are standardized. Witness that maps from some countries do not employ WGS-84. United Kingdom uses OSGB36 rather than WGS84, and a different Elipsoid too (Airy 1830) which is a better fit locally. ian ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] LEAPSECS Digest, Vol 51, Issue 22
GPS Time actually come from a paper clock composed of all satellite and ground station clocks: http://tycho.usno.navy.mil/gpstt.html. -- Richard Quoting Tony Finch d...@dotat.at: On Mon, 7 Feb 2011, Steve Allen wrote: Until there is an ensemble of cesium chronometers not on the surface of the earth there is no easy way to measure the potential depth to 1e-10, so the corrections currently being used to compensate for the NIST and PTB chronometers being about a mile high are as good as things can get. The PTB campus is at about 75m above sea level. Also, doesn't the GPS count as an ensemble of atomic clocks? Tony. -- f.anthony.n.finch d...@dotat.at http://dotat.at/ HUMBER THAMES DOVER WIGHT PORTLAND: NORTH BACKING WEST OR NORTHWEST, 5 TO 7, DECREASING 4 OR 5, OCCASIONALLY 6 LATER IN HUMBER AND THAMES. MODERATE OR ROUGH. RAIN THEN FAIR. GOOD. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Meeting with Wayne Whyte
Agreed. And I believe that the terms TU0, TU1, and TU2 and the corresponding UT0, UT1, and UT2, predated the introduction of UTC and so it was natural to extend the series to TUC and UTC for Coordinated Universal Time. -- Richard Quoting Steve Allen s...@ucolick.org: On Tue 2011-02-01T16:53:24 -0700, Rob Seaman hath writ: What would that be in French? Probably Temps something something, right? The acronym would presumably have to avoid both UTC for the English and Txx for the French. Maybe CUT as described at: http://www.nist.gov/pml/div688/utcnist.cfm#cut Alas for NIST, this web snippet is not consistent with the written record in the proceedings of the CCIR 1970 Plenary Assembly. In the adopted recommendation on page 227 of volume 3 (which is in French) the only time scale repeatedly mentioned is temps universel (TU). In the description of the events leading to the new recommendation on page 182 of volume 7 (which is in English) the text reads improvement of the U.T.C. (Universal Coordinated Time) system but the summary of the content of the new recommendation repeatedly and only mentions Universal Time (U.T.) I deem the NIST explanation to be ex post facto and ad hoc. -- Steve Allen s...@ucolick.orgWGS-84 (GPS) UCO/Lick ObservatoryNatural Sciences II, Room 165Lat +36.99855 University of CaliforniaVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] American Scientist
Dave: If you need and GPS(GNSS)-related input, just let me know. -- Richard Quoting Finkleman, Dave dfinkle...@agi.com: I have been invited to write an article on this subject for the quarterly journal of Sigma Xi, American Scientist. Someone read our AAS paper and thought the subject would be appropriate for the diverse technical community. The style is that the report be understandable to those with a solid technical background, neither experts nor laymen. I welcome suggestions, and I will share authorship with all willing to work on it. BTW: The Islamic month begins with heliacal rising of the crescent Moon. However, contrary to my warped recollection, the Islamic day cycle is governed by the Sun. However, there is still a difference between the start of the Moslem day (sunset or Maghrib - which means west) and the start of the Hebrew day (verifiable star sightings). Dave Finkleman Senior Scientist Center for Space Standards and Innovation Analytical Graphics, Inc. 7150 Campus Drive Colorado Springs, CO 80920 Phone: 719-510-8282 or 719-321-4780 Fax: 719-573-9079 Discover CSSI data downloads, technical webinars, publications, and outreach events at www.CenterForSpace.com. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Fwd: IERS Message No. 180 - revised version
- Forwarded message from central_bur...@iers.org - Date: Fri, 7 Jan 2011 16:40:53 +0100 From: central_bur...@iers.org Subject: IERS Message No. 180 - revised version To: messa...@iers.org Please note: This is a corrected version of IERS Message No. 180 distributed on January 5, 2011. IERS Message No. 180January 07, 2011 Revision of IERS Earth Rotation Series effective 1 February 2011 The current series of IERS Earth Orientation Parameters (EOP) provides the official transformation between the International Celestial Reference Frame (ICRF) and the International Terrestrial Reference Frame (ITRF). In order to be consistent with the recently released ITRF2008, the IERS EOP C04 is being revised. The new solution 08C04 is the reference solution starting on 1 February 2011. Relative to 05C04, changes in the EOP series consist of 1) A negligible bias in x-pole and a bias of about -50 +/- 25 microarcseconds in y-pole in the sense of y (08C04) - y (05C04); 2) Changes in UT1-TAI and celestial pole offsets are respectively on the order of 2 microseconds, 1, and 17 microarcseconds which are at the level of the WRMS between IVS individual solutions. Other IERS EOP series (Bulletin B, C01) will be expressed in this new system consistent with ITRF2008 starting with solutions after 1 February 2011. The Rapid Service/Prediction Center solutions (Bulletin A and daily) will be expressed in the new system starting with solutions made on 1 February 2011. The new version of the C 04 computed in the new system is now called IERS 08 C 04. IERS 08 C 04 series will be available at: ftp://hpiers.obspm.fr/iers/eop/eopc04 A notice describing its characteristics will be available at: ftp://hpiers.obspm.fr/iers/eop/eopc04/C04.guide.pdf Past version of C 04 can be downloaded until 30 June 2011 from: ftp://hpiers.obspm.fr/iers/eop/eopc04_05/ Thank you for your cooperation D. Gambis, C. Bizouard, Earth Orientation Center, Paris Observatory B. Luzum, N. Stamatakos, IERS Rapid Service/Predictions Center, US Naval Observatory IERS Messages are edited and distributed by the IERS Central Bureau. To submit texts for distribution and to subscribe or unsubscribe, please write to central_bur...@iers.org. Archives: http://www.iers.org/Messages/ - End forwarded message - === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Focus in the debate, alternative proposal
Anyone else get a Doctor Who disappearing TARDIS mug for Christmas? ;-) -- Richard P.S. I also got a sundial (just in case the ITU decision goes the wrong way). Quoting Rob Seaman sea...@noao.edu: Currently local time zones range from Christmas Island, on Z+14:00, to Midway Island, on Z-11:00 (I use Z to avoid the UTC/UT/GMT argument). So there's always somewhere where it's not Sunday. That should make Doctor Who aficionados happy. He never lands on Sunday. (Perhaps he's trying to avoid leap seconds, with the implication that my suggestion is guaranteed soon to be adopted :-) By all means let's gather more requirements from locations ranging Midway to Christmas. Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Ghosts of Leap-seconds past and future
I have been asked to remind list members of the presentation by Ron Beard, the chairman of ITU-R Working Party 7A, at ION GNSS 2010. The PowerPoint slides can be downloaded from here: http://www.navcen.uscg.gov/pdf/cgsicMeetings/50/%5B16%5DITU_Status_UTC_Revision_CGSIC_50th.pdf. Here are the conclusions, summary, and actions from the presentation: CONCLUSIONS Major scientific and GNSS organizations have not taken issue with the subject There has been ample opportunity and encouragement to contribute The lack of response has been interpreted as having no concern and thus no established opinion Little information on quantitative costs has been provided The few estimates offered seem to be guesses at best Few observers noted there are costs associated with maintaining the status quo that may or may not be mitigated Most experts in time metrology agree on the necessity for the change and offer technical support The Consultative Committee on Time and Frequency strongly recommends proceeding with a decision so enough time is available for any necessary software and systems modifications SUMMARY Documents demonstrate a clear misunderstanding of the definitions and applications of time scales and system times for internal synchronization o Indications that users have the choice between UTC, TAI, UT1, GPS Time for their applications is incorrect o UTC is the only international standard time scale, represented by local approximations in time laboratories, that should be used for worldwide time coordination and measurement traceability o TAI is not an option for applications needing a continuous reference as it has no means of dissemination, and it is not physically represented by clocks o GPS time is not a reference time scale, it is an internal time for GPS system synchronization, as other GNSS system times would be o A variety of continuous internal system time scales have proliferated to provide a solution to the problems associated with discontinuities in UTC The existence of multiple time scales creates potential problems in operational use as well as conceptual confusion on the proper definition and roles of time references ACTIONS Working Party 7A exhausted technical considerations and studies Consensus not reached on other than technical grounds Submitted to Study Group 7 for resolution So far, I have not seen any reports from Study Group 7 subsequent deliberations. -- Richard Langley Quoting Rob Seaman sea...@noao.edu: God bless us, every one! On Dec 26, 2010, at 8:40 PM, Richard B. Langley wrote: Quoting Rob Seaman sea...@noao.edu: The ITU, rather, have monomaniacally pursued one-and-only-one NON-solution for a decade, and have assiduously avoided characterizing the problem they claim to seek to solve. Slander those who tell it ye! Admit it for your factious purposes, and make it worse! And bide the end! So yes - I will continue to rattle my chains. Dare we hope for a Scrooge-like transformation of the ITU? ;-) ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Ghosts of Leap-seconds past and future
Quoting Rob Seaman sea...@noao.edu: The ITU, rather, have monomaniacally pursued one-and-only-one NON-solution for a decade, and have assiduously avoided characterizing the problem they claim to seek to solve. Slander those who tell it ye! Admit it for your factious purposes, and make it worse! And bide the end! So yes - I will continue to rattle my chains. Dare we hope for a Scrooge-like transformation of the ITU? ;-) -- Richard === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] DCF 77
The GPS broadcast navigation message includes advanced notice of a leap second: From IS-GPS-200: 20.3.3.5.2.4 Coordinated Universal Time (UTC). Page 18 of subframe 4 includes: (1) the parameters needed to relate GPS time to UTC, and (2) notice to the user regarding the scheduled future or recent past (relative to NAV message upload) value of the delta time due to leap seconds (?tLSF), together with the week number (WNLSF) and the day number (DN) at the end of which the leap second becomes effective. -- Richard Langley Quoting Finkleman, Dave dfinkle...@agi.com: Do any sources of precise, accrued time have a leap second warning bit as DCF 77 does?Is the philosophy of leap second warning in DCF 77 a good paradigm for helping implement the leap second broadly? Dave Finkleman Senior Scientist Center for Space Standards and Innovation Analytical Graphics, Inc. 7150 Campus Drive Colorado Springs, CO 80920 Phone: 719-510-8282 or 719-321-4780 Fax: 719-573-9079 Discover CSSI data downloads, technical webinars, publications, and outreach events at www.CenterForSpace.com. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] DCF 77
Quoting Tom Van Baak t...@leapsecond.com: TAI, GPS, or UTC out of a GPS receiver. One downside is that you have to wait up to 12.5 seconds for the leap second information to show up, which can cause timing issues with cold-start receivers. The current GPS navigation message lasts 12.5 MINUTES. -- Richard Langley === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] php breaks if UTC has no leap seconds?
USNO predicts UT1-UTC. In Bulletin A http://maia.usno.navy.mil/ser7/ser7.dat, they predict daily values for a year in advance but only provide an error estimate up to 40 days in advance. Elsewhere http://maia.usno.navy.mil/ser7/deltat.preds, longer-term predictions are given; supposedly updated annually. -- Richard Langley Quoting Warner Losh i...@bsdimp.com: On 12/09/2010 17:35, Rob Seaman wrote: On Dec 9, 2010, at 3:53 PM, Steve Allen wrote: This is the first example I've come across where a widely used API will break if UTC does not continue to have leap seconds. Has anyone even considered a Y2K style inventory? Absence of evidence is not...oh, what's the point? Keep in mind that while a code change would required to fetch DUT1 from the internet or other source, the API could continue to function, but with an increased uncertainty as the date is farther into the future. If this is an important number to know, I'm sure someone will publish a model that tries to approximate dUT1 and gives an uncertainty range that presumably expands the further into the future we go. You're correct about the question: How many of these interfaces are there, and what is the implication for increasing the error in the present calculation from 1s? For php, I doubt anybody would care for the cases likely to be in error... For other things, likely they care more. Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Coming of age in the solar system
Some of us have designed/rebuilt sundials: http://www.new-brunswick.net/new-brunswick/fredericton/page1.html http://www.mail-archive.com/sund...@uni-koeln.de/msg09972.html. There is a very knowledgeable sundial group, which includes a number of scientists and others familiar with the astronomical niceties: https://lists.uni-koeln.de/mailman/listinfo/sundial. -- Richard Quoting Roger Stapleton j...@st-andrews.ac.uk: On Mon, 6 Sep 2010, Poul-Henning Kamp wrote: In message fd9f9d07-2a21-4f72-a10a-f7b91b7c1...@noao.edu, Rob Seaman writes: On Sep 5, 2010, at 8:00 AM, Poul-Henning Kamp wrote: Oh! Other than astronomy - the one and only place we've looked sufficiently well enough to know the answer. So far I don't recall one single example having been proffered outside astronomy ? Perhaps there is nobody on this list who designs and builds sundials? They are usually artsist/craftsman and NOT astronomers. Roger This argument of yours would be a lot stronger if you could at least identify the index-case for the class. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs Roger Stapleton j...@st-and.ac.uk University of St.Andrews, School of Physics Astronomy North Haugh, St.Andrews, Fife. KY16 9SS Fax 01334-463104 Phone - rarely in the office, use e-mail! The University of St Andrews is a charity registered in Scotland: No SC013532 ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] The Debate over UTC and Leap Seconds
Many thanks for the link, Steve. There should also be an update at the ION GNSS 2010 meeting: http://www.navcen.uscg.gov/pdf/ION_CGSIC_program2010.pdf. A summary of the current status will likely get into GPS World magazine and/or its website. -- Richard Quoting Steve Allen s...@ucolick.org: The Debate over UTC and Leap Seconds is the title of a paper from the AIAA last week with contribution from P. Kenneth Seidelmann It is probably the most comprehensive publicly-available paper since the Metrologia paper many years back. It's available at http://www.agi.com/downloads/resources/user-resources/downloads/whitepapers/DebateOverUTCandLeapSeconds.pdf -- Steve Allen s...@ucolick.orgWGS-84 (GPS) UCO/Lick ObservatoryNatural Sciences II, Room 165Lat +36.99855 University of CaliforniaVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] leap second dating
Quoting Steve Allen s...@ucolick.org: On Mon 2009-11-16T13:42:32 -0700, M. Warner Losh hath writ: Hmmm. These papers are interesting reading. They present some of the clearest history of parts of this story that I've seen... At least the public story... Regarding the story, it seems this is almost out November 25th, apparently. -- Richard Langley http://www.amazon.com/Time-Earth-Rotation-Atomic-Physics/dp/3527407804/ The table of contents looks like it tells a delicious amount of the history. -- Steve Allen s...@ucolick.orgWGS-84 (GPS) UCO/Lick ObservatoryNatural Sciences II, Room 165Lat +36.99855 University of CaliforniaVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] it's WP7A week in Geneva
Tried sending a copy of Ron Beard's viewgraphs as it might be some time before they show up on the Coast Guard web site but the message is held up awaiting moderator approval. Here is a link to them instead http://gauss.gge.unb.ca/ITU_future_UTC_(CGSIC_49th).ppt. -- Richard Langley Quoting Richard B. Langley l...@unb.ca: http://www.gpsworld.com/gnss-system/cgsic-%E2%80%93-the-rest-better-late-never-8956 -- Richard Langley Quoting Richard B. Langley l...@unb.ca: There will likely be a report on anything significant at the CGSIC meeting in Savannah the week after next http://www.navcen.uscg.gov/cgsic/meetings/49thmeeting/49th_CGSIC_Meeting_Agenda.htm. -- Richard Langley Quoting M. Warner Losh i...@bsdimp.com: In message: 20090909172025.gm21...@ucolick.org Steve Allen s...@ucolick.org writes: : On Tue 2009-09-08T18:39:31 -0700, Steve Allen hath writ: : The WP7A is meeting in Geneva this week. : : There are two documents about UTC on their table as seen here : http://www.itu.int/md/R07-WP7A-C/en : one from People's Republic of China, : and another from BIPM (which, curiously, is not about question 236/7) : : In response to several notes, yes, these are protected, so the only : broadly visible aspects are the authors and titles. It seems to me : that the ITU-R operates in a sort of 19th century diplomatic mode. Any chance the docs will leak out after the meeting? There's been several leaks in the past of similar docs... Do we know, broadly, what the docs say? Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] it's WP7A week in Geneva
http://www.gpsworld.com/gnss-system/cgsic-%E2%80%93-the-rest-better-late-never-8956 -- Richard Langley Quoting Richard B. Langley l...@unb.ca: There will likely be a report on anything significant at the CGSIC meeting in Savannah the week after next http://www.navcen.uscg.gov/cgsic/meetings/49thmeeting/49th_CGSIC_Meeting_Agenda.htm. -- Richard Langley Quoting M. Warner Losh i...@bsdimp.com: In message: 20090909172025.gm21...@ucolick.org Steve Allen s...@ucolick.org writes: : On Tue 2009-09-08T18:39:31 -0700, Steve Allen hath writ: : The WP7A is meeting in Geneva this week. : : There are two documents about UTC on their table as seen here : http://www.itu.int/md/R07-WP7A-C/en : one from People's Republic of China, : and another from BIPM (which, curiously, is not about question 236/7) : : In response to several notes, yes, these are protected, so the only : broadly visible aspects are the authors and titles. It seems to me : that the ITU-R operates in a sort of 19th century diplomatic mode. Any chance the docs will leak out after the meeting? There's been several leaks in the past of similar docs... Do we know, broadly, what the docs say? Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] it's WP7A week in Geneva
There will likely be a report on anything significant at the CGSIC meeting in Savannah the week after next http://www.navcen.uscg.gov/cgsic/meetings/49thmeeting/49th_CGSIC_Meeting_Agenda.htm. -- Richard Langley Quoting M. Warner Losh i...@bsdimp.com: In message: 20090909172025.gm21...@ucolick.org Steve Allen s...@ucolick.org writes: : On Tue 2009-09-08T18:39:31 -0700, Steve Allen hath writ: : The WP7A is meeting in Geneva this week. : : There are two documents about UTC on their table as seen here : http://www.itu.int/md/R07-WP7A-C/en : one from People's Republic of China, : and another from BIPM (which, curiously, is not about question 236/7) : : In response to several notes, yes, these are protected, so the only : broadly visible aspects are the authors and titles. It seems to me : that the ITU-R operates in a sort of 19th century diplomatic mode. Any chance the docs will leak out after the meeting? There's been several leaks in the past of similar docs... Do we know, broadly, what the docs say? Warner ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] ISO 8601 Z designator improper before 1972?
Quoting Poul-Henning Kamp p...@phk.freebsd.dk: In message 625029c6e1f142b688cebedecdfad...@grendel, Gerard Ashton writes: Similarly, within ISO 8601, Z designates UTC and any meaning it may have had for most of the 20th century outside that standard is irrelevant. The meaning 'Z' had before ISO8601, and which ISO8601 codified, was UTC. If you look at the Canadian time-station CHU's QSL card: http://flickr.com/photos/bneely/223853969/ You will notice that the timezones have letters on the illustration on the wall. It is not clear to me if the zero meridian have 'N' or 'Z' as designator. Neither. It is M. I have a scan of a BW photo of the painting if anyone is interested. -- Richard Langley The painting is supposed to despict a meeting in 1879 where Sandford Flemming first laid out his idea for timezones. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] ISO 8601 Z designator improper before 1972?
I don't know where the original is now. Did a Google search but couldn't find it. The painting was one of 40 done for the now defunct insurance company, Confederation Life, by Woods, a prolific commercial artist. A fire gutted the Confereration Life building in Toronto in the 1970s. Don't know if the paintings were there or, if they were there, were saved or were destroyed. But, apparently, there is a print at Cambridge University http://janus.lib.cam.ac.uk/db/node.xsp?id=EAD%2FGBR%2F0115%2FRCMS%20344 Prints also at the Royal Alberta Museum http://www.royalalbertamuseum.ca/gallery/retro/retro1969.htm While searching, came across this http://www.histori.ca/minutes/minute.do?id=10182 which used to run as a public education service on Canadian TV. -- Richard Langley Quoting Poul-Henning Kamp p...@phk.freebsd.dk: In message 1234206791.4990804737...@webmail.unb.ca, Richard B. Langley writ es: It is not clear to me if the zero meridian have 'N' or 'Z' as designator. Neither. It is M. I have a scan of a BW photo of the painting if anyone is interested. Of course, (M)eridian :-) I'd be more interested in if you know where the painting is ? I'm probably going to BSDcan in Ottawa again this year, and if it is within range I would like to see it myself. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] DCF77, HBG, MSF, two out of three
The clock on my Bell Mobility (CDMA) phone is clicking over about 2 seconds FAST. Quoting Brian Garrett mgy1...@cox.net: - Original Message - From: b...@po.cwru.edu To: Leap Second Discussion List leapsecs@leapsecond.com Sent: Thursday, January 01, 2009 1:57 PM Subject: Re: [LEAPSECS] DCF77, HBG, MSF, two out of three From: Poul-Henning Kamp p...@phk.freebsd.dk DCF77 got right, as always. HBG also got it right this time. MSF still fumbles the DUT1 bits. http://phk.freebsd.dk/Leap/20081231/ Very nice. Alas, my receiver isn't close enough to the computer and I didn't think to record the signal. WWV got it right, as far as I could tell. I'm not sure if the DUT1 bits were correct in the first minute or not. Sprint's cellular network has still NOT got it right,after four days. My cell phone, whose time display used to change right on the tick of the UTC second, is now one second slow. Sprint is a CDMA network, which as far as I know runs on GPS time, so it would appear that some code indicating the number of seconds difference between UTC and GPS ws not updated. GSM networks like T-Mobile and ATT are just fine with wall-clock time so they can happily be off by two minutes and no one but us anal-retentives will know or care :) Verizon is CDMA so they should have updated, unless they goofed like Sprint. Brian Garrett ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] DCF77, HBG, MSF, two out of three
CHU got it right this time. Last time there was a change in the DUT1 value effective 1 January in addition to the leap second. The notice from IERS was sent late and the people responsible for inputting the new DUT1 value were already on their Christmas/New Year break when it arrived. Quoting Poul-Henning Kamp p...@phk.freebsd.dk: DCF77 got right, as always. HBG also got it right this time. MSF still fumbles the DUT1 bits. http://phk.freebsd.dk/Leap/20081231/ -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Automation
Quoting Rob Seaman sea...@noao.edu: Let's give it a try. The online cache of Bulletin A at IERS only goes back to 2005. Presumably the earlier ones are stashed somewhere. http://cddis.gsfc.nasa.gov/reports.html Also, data can be extracted from here: http://maia.usno.navy.mil/search/search.html Now, back to exam marking. Oh, and by the way, with reference to Time Lords, did anyone else get a Tardis USB hub for Christmas? ;-) === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Schedule for success
Quoting Steve Allen s...@ucolick.org: The geodetic longitude of the Greenwich transits is 5 arc seconds west of the International Meridian defined by the global, satellite-geocentered, VLBI-oriented reference frames. That's less than one second of time -- but it's mostly irrelevant to GMT. Of those 5 arcseconds difference, the major component is due to the E/W component of the deflection of vertical at Greenwich. That is to say, at Greenwich up is 5 arc seconds different than geocentrically radial. Steve: The 5 arcseconds is the difference between two geodetic longitudes, so I believe deflection of the vertical is not a component of this difference, it has already been taken into account. The drift from the Airy meridian is due to i) The merging of transit measurements from many global observatories by the BIH. ii) The the shift of the Greenwich transit observations to PZT measurements at Herstmonceux. iii) The introduction of the satellite Doppler technique (Transit) to help in establishing the BIH meridian; the Doppler datum turned out to have a different longitude origin. iv) Misalignment of the series of WGS reference meridians with that of BIH. Further details here: http://www.nmm.ac.uk/explore/astronomy-and-time/astronomy-facts/history/the-longitude-of-greenwich http://en.wikipedia.org/wiki/Prime_Meridian === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Schedule for success
Quoting Poul-Henning Kamp p...@phk.freebsd.dk: In message 1230733996.495b82acce...@webmail.unb.ca, Richard B. Langley writ es: iii) The introduction of the satellite Doppler technique (Transit) to help in establishing the BIH meridian; the Doppler datum turned out to have a different longitude origin. iv) Misalignment of the series of WGS reference meridians with that of BIH. So which datum is used for the zero meridian, which defines the UT* family of timescales ? That would be the current ITRF as established by the IERS: http://www.iers.org/MainDisp.csl?pid=42-17 It is a realization of the ITRS: http://www.iers.org/MainDisp.csl?pid=97-108 === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Schedule for success
Quoting Poul-Henning Kamp p...@phk.freebsd.dk: In message 1230733996.495b82acce...@webmail.unb.ca, Richard B. Langley writ es: iii) The introduction of the satellite Doppler technique (Transit) to help in establishing the BIH meridian; the Doppler datum turned out to have a different longitude origin. iv) Misalignment of the series of WGS reference meridians with that of BIH. So which datum is used for the zero meridian, which defines the UT* family of timescales ? This might also be relevant: ftp://itrf.ensg.ign.fr/pub/itrf/WGS84.TXT === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Schedule for success
Quoting Poul-Henning Kamp p...@phk.freebsd.dk: And since WGS84 is not rigidly linked to ITRS, doesn't that mean that in order to use DUT1 broadcasts to point a telescope (precisely[1]) you also need to the ITRS/WGS84 difference at your place ? Has anybody calculated what the worst case DUT1 difference is in the WGS84 datum ? The current version of WGS84 differs from the current version of ITRF by only a few centimetres. WGS84 was purposely updated to agree as closely as possibly with ITRF. === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] Cheating means more planning, not less
I think IERS Bulletin A might represent the current state of the art for predicting Earth orientation. It is produced by USNO. Latest bulletin is here: http://www.iers.org/products/6/11769/orig/bulletina-xxi-052.txt. It provides a table of UT1-UTC values to the end of 2009. It also provides an estimated function and its standard deviation that can be used to extend the table. How accurate are the predictions (especially the long-term ones) really? One would have to compare one of the historical empirical functions with actual UT1 data. Not sure if anyone has done that recently. Perhaps Demetrios knows? -- Richard Langley P.S. For those wanting to refresh their memories on the details of the history of the leap-second business, have a look at http://tycho.usno.navy.mil/leapsec.html. Quoting Rob Seaman sea...@noao.edu: What exactly is the current state of the art for predicting Earth orientation? It is a shame that there are no lurkers here who could answer that question. === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Fwd: Re: Leap second is back
List members might be interested in the message below posted to the Sundial List--yes, some of us are interested in these devices that provide true time ;-). Not that this posting will likely sway current diverse and seemingly entrenched opinions of some members (one way or the other). By the way, I must confess, that reading some of the postings reminds me of the Dilbert cartoon strip at times. ;-) Anyway, happy holidays to all. -- Richard Langley Links to The Times items: http://www.timesonline.co.uk/tol/comment/leading_article/article5361349.ece http://www.timesonline.co.uk/tol/comment/letters/article5385619.ece http://www.timesonline.co.uk/tol/news/uk/science/article5361670.ece http://www.timesonline.co.uk/tol/comment/letters/article5372021.ece http://www.timesonline.co.uk/tol/news/uk/science/article5361935.ece - Forwarded message from Frank King frank.k...@cl.cam.ac.uk - Date: Sat, 27 Dec 2008 09:15:30 + From: Frank King frank.k...@cl.cam.ac.uk Reply-To: Frank King frank.k...@cl.cam.ac.uk Subject: Re: Leap second is back To: Sundial List sund...@uni-koeln.de Dear All, On 9 December, Fred Sawyer reminded us that there will be a leap second at the end of this month. He suggested that the proposal to eliminate Leap Seconds has not been adopted. It is true that this proposal has not yet been adopted but the proposal has certainly not been abandoned. There was a worrying report in the London Times newspaper of 18 December noting that the ITU is still keen to get rid of Leap Seconds. The Times also printed a defence of the Leap Second by David Rooney (Curator of timekeeping at the Royal Greenwich Observatory) and a further defence by my colleague Markus Kuhn (whose office is next to mine!). I mentioned the report to my friend John Chambers who was Head of the UK Time Service from 1993 to 1996 and prompted him to write a letter to the Times giving his views. His letter, as published, can be found at: http://www.timesonline.co.uk/tol/comment/letters/article5385619.ece His letter, as sent (before the Letters Editor got hold of it!), can be found below my signature. Very diplomatically, he notes that it really is no business of the ITU to mess about with Civil Time. Unfortunately, the published version leaves out John's note about sundials. [Do Times readers have no interest in these instruments?] Equally unfortunately, the published version leaves out the important comment that those who want an unchanging timescale can use GPS time. Moreover, GPS time is provided free! Best wishes Frank King Cambridge, UK Original Letter about Leap Seconds as sent to the Times Letters to the Editor, The Times - [This letter is sent exclusively to The Times] Sir, Any intention to interfere with the current worldwide arrangements for civil time by minutes, or even hours (third leader and report (page 8) December 18, letters December 19, 20) are surely beyond the competence of the International Telecommunications Union (ITU). The ITU's scope extends only to time signals as broadcast. Reform of civil time is as important as calendar reform, where the ramifications of the Vatican initiative in 1582 took hundreds of years to settle. Coordinated Universal Time (UTC) is a compromise which has served us well since 1972 as the basis for time zones. It provides a timescale within one second of mean solar time for everyday use. It has seconds markers coincident with the more regular atomic timescale used, for example, in GPS and deep-space navigation. The two are simply related: GPS time is 14s ahead of UTC until after the leap second at the end of this month, then it will be 15s ahead. Sundials are used worldwide to tell the time, requiring neither fuel nor moving parts. Some can be read to an accuracy of better than a minute. Traditional navigation, based on observation of sun and stars, loses less than 400 metres in accuracy when UTC is used. However much train time- keeping improves we can live within these limits in everyday life. Those who need to live a precise life, or whose systems depend on there being 60 seconds in every minute, can already use GPS time. There is no need for another time scale. (Mr) John Chambers (Head of UK Time Service 1993-96) Koskenpääntie 79, 42300 Jämsänkoski, Finland --- https://lists.uni-koeln.de/mailman/listinfo/sundial - End forwarded message - === Richard B. LangleyE-mail: l...@unb.ca Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca
Re: [LEAPSECS] drift of TAI
On Mon, 15 Sep 2008, Steve Allen wrote: Along those lines ... The earliest use of the term UTC as such (and TUC in the French) that I have found is in the Jan/Feb 1964 Bulletin Horaire from the BIH. This was the first issue done by Guinot after Anna Stoyko gave it up. Does anyone know of a use of the term UTC/TUC which predates that? At the time I wrote this for lay people http://gauss.gge.unb.ca/GMT.UT.and.the.RGO.html (scroll down to The Origin of UTC), I knew of nothing earlier. -- Richard -- Steve Allen [EMAIL PROTECTED] WGS-84 (GPS) UCO/Lick ObservatoryNatural Sciences II, Room 165 Lat +36.99858 University of CaliforniaVoice: +1 831 459 3046 Lng -122.06014 Santa Cruz, CA 95064http://www.ucolick.org/~sla/Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Leap Second Announced by IERS (fwd)
-- Forwarded message -- Date: Fri, 4 Jul 2008 09:25:03 -0300 From: Richard B. Langley [EMAIL PROTECTED] Reply-To: Canadian Space Geodesy Forum [EMAIL PROTECTED], Richard B. Langley [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: Leap Second Announced by IERS [[The integer second offset between GPS System Time and UTC will increase to 15 seconds after the leap second insertion. More info on leap seconds here: http://tycho.usno.navy.mil/leapsec.html. -- RBL]] INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 e-mail: [EMAIL PROTECTED] http://hpiers.obspm.fr/eop-pc Paris, 4 July 2008 Bulletin C 36 To authorities responsible for the measurement and distribution of time UTC TIME STEP on the 1st of January 2009 A positive leap second will be introduced at the end of December 2008. The sequence of dates of the UTC second markers will be: 2008 December 31, 23h 59m 59s 2008 December 31, 23h 59m 60s 2009 January 1, 0h 0m 0s The difference between UTC and the International Atomic Time TAI is: from 2006 January 1, 0h UTC, to 2009 January 1 0h UTC : UTC-TAI = - 33s from 2009 January 1, 0h UTC, until further notice : UTC-TAI = - 34s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC or to confirm that there will be no time step at the next possible date. Daniel GAMBIS Head Earth Orientation Center of IERS Observatoire de Paris, France === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === [To unsubscribe from CANSPACE, send the following message to [EMAIL PROTECTED] (DO NOT send it to CANSPACE) using the same e-mail address you used to subscribe to CANSPACE initially: SIGNOFF CANSPACE. If you do not receive a confirmation within a day or so, re-send your request to [EMAIL PROTECTED].] ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] Book: One time fits all : the campaigns for global uniformity
FYI. Bartky also wrote Selling the True Time: Nineteenth-Century Timekeeping in America (Stanford Univ. Press, Stanford, CA, 2000) and died last December. Obit here: http://www.washingtonpost.com/wp-dyn/content/article/2007/12/23/AR2007122302355.html Bartky, Ian R. One time fits all : the campaigns for global uniformity / Ian R. Bartky. Stanford, CA : Stanford University Press, 2007. xxv, 292 p. : ill., maps ; 24 cm. [Includes bibliographical references and index.] ISBN: 0-8047-5642-2 (Cloth/HB 49.95 USD) LC Class: QB223 Dewey: 389/.17 22 LC Subject Headings: Time--Systems and standards. One Time Fits All provides the first full framework for understanding attributes of civil time, which is used throughout the world today. It focuses on three components of uniform time all linked to the prime meridian at Greenwich - the International Date Line, the worldwide system of Standard Time zones, and Daylight Saving Time (Summer Time) - tracing the story of their beginnings and eventual acceptance from original sources in Europe, Great Britain, Canada, and the United States. The book concludes with an examination of the recent changes in America's Daylight Saving Time that took effect in 2007. === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
[LEAPSECS] IERS Message No. 129: Plots of Earth Orientation Data (fwd)
-- Forwarded message -- Date: Wed, 9 Apr 2008 07:50:40 +0200 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: IERS Message No. 129: Plots of Earth Orientation Data IERS Message No. 129 April 09, 2008 Plots of Earth Orientation Data Some of the Earth Orientation Data provided by the IERS (see http://www.iers.org/MainDisp.csl?pid=36-9) can now be visualized by a simple click on the graphic symbols at this web page. The data include pole coordinates, UT1-UTC, LOD, and celestial pole offsets. The plots may be enlarged by clicking on them. Please be reminded also of the interactive tools for selecting, plotting, and analyzing time series of the Earth orientation available at the IERS Earth Orientation Centre ((http://hpiers.obspm.fr/eop-pc), which were announced in IERS Message No. 46. Bernd Richter and Wolfgang Schwegmann IERS Central Bureau IERS Messages are edited and distributed by the IERS Central Bureau. To subscribe or unsubscribe, please write to [EMAIL PROTECTED]. Archives: http://www.iers.org/iers/publications/messages/ ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] How good could civil timekeeping be?
On Fri, 15 Feb 2008, Tony Finch wrote: For a shorter version see Seidelmann's writeup in Explanatory Supplement to the Astronomical Almanac, University Science Books, 1992 Not the more recent edition? http://www.amazon.com/gp/product/1891389459/ Is that just a paperback version of the 1992 hardcover edition? Any text differences at all? === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
