From sla at ucolick.org Sat Aug 1 19:41:14 2015 From: sla at ucolick.org (Steve Allen) Date: Sat, 1 Aug 2015 16:41:14 -0700 Subject: [LEAPSECS] state of the leap Message-ID: <20150801234114.GA328@ucolick.org> The AP has been publishing its video archives. One snip contains their coverage of the 2012 ITU-R Radiocommnication Assembly vote, or rather, lack of vote, on the draft proposal to abandon leap seconds. https://www.youtube.com/watch?v=ez8HG_bCLno The Australian Communications and Media Authority still has its web page showing the APG15-4 session that was held at the APT meeting in Bangkok during February. http://www.acma.gov.au/Industry/Spectrum/Spectrum-planning/International-planning-ITU-and-other-international-planning-bodies/wrc-15-agenda-item-114 That web page originally had the methods A1, A2, B, C1, and C2 from the CPM sessions held during 2014. Since the CPM15-2 meeting in March/April it also includes method D. The CPM web page at ITU http://www.itu.int/md/R12-CPM15.02-C-0111/en shows that method D was proposed by 6 nations: UAE, Algeria, Egypt, Jordan, Qatar, and Sudan. The European Conference of Postal and Telecommunications Administrations gives a view into the other proposed methods. They have several documents giving the current status, full draft text, and analysis of the pros and cons of the various methods at http://www.cept.org/ecc/groups/ecc/cpg/page/cept-briefs-and-ecps-for-wrc-15 Method A is supported by France. Method C is supported by Russia. I am certain that the diplomats are continuing to negotiate. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From seaman at noao.edu Tue Aug 4 20:14:20 2015 From: seaman at noao.edu (Rob Seaman) Date: Tue, 4 Aug 2015 17:14:20 -0700 Subject: [LEAPSECS] IEEE Symposium on Precision Clock Synchronization ? Message-ID: <7DE15026-99CE-4458-8610-DC75BFBB5507@noao.edu> Howdy! Who here may be attending ISPCS in Beijing this October? http://www.ispcs.org/2015/ Rob -------------- next part -------------- An HTML attachment was scrubbed... URL: From tvb at LeapSecond.com Wed Aug 12 19:47:14 2015 From: tvb at LeapSecond.com (Tom Van Baak) Date: Wed, 12 Aug 2015 16:47:14 -0700 Subject: [LEAPSECS] Why the Greenwich meridian moved Message-ID: <89FCDF99E5004EE3A2AF940DB65ACAD3@pc52> For those of you that have been at this a while, the exact location of zero longitude is very interesting. Not just for astronomy, but also in the history of precise timekeeping. An alert reader pointed me to a great article, just published (and free PDF). Why the Greenwich meridian moved http://link.springer.com/article/10.1007/s00190-015-0844-y http://link.springer.com/content/pdf/10.1007%2Fs00190-015-0844-y.pdf See also: http://leapsecond.com/pages/meridian/ for my recent visit. /tvb From hmurray at megapathdsl.net Fri Aug 14 15:58:54 2015 From: hmurray at megapathdsl.net (Hal Murray) Date: Fri, 14 Aug 2015 12:58:54 -0700 Subject: [LEAPSECS] Why the Greenwich meridian moved In-Reply-To: Message from "Tom Van Baak" of "Wed, 12 Aug 2015 16:47:14 PDT." <89FCDF99E5004EE3A2AF940DB65ACAD3@pc52> Message-ID: <20150814195854.8CDBA406057@ip-64-139-1-69.sjc.megapath.net> That story made NPR yesterday. The audio is only 30 seconds. GPS Locates True Greenwich Meridian Line http://www.npr.org/2015/08/14/432192377/gps-locates-true-greenwich-meridian-li ne > When GPS arrived 30 years ago, the real prime meridian was revealed. It's > 334 feet to the east, and it's currently marked by a trashcan. -- These are my opinions. I hate spam. From sla at ucolick.org Sat Aug 29 14:32:13 2015 From: sla at ucolick.org (Steve Allen) Date: Sat, 29 Aug 2015 11:32:13 -0700 Subject: [LEAPSECS] countdown to WRC-15 Message-ID: <20150829183213.GA25467@ucolick.org> Regional meetings continue about the fate of the leap second as various bodies consider their position on WRC-15 Agenda Item 1.14. http://www.itu.int/en/ITU-R/conferences/wrc/2015/Pages/reg-prep.aspx shows that the Arab group just finished, and the European and Russian meetings are still pending. Next week is one more meeting of all the regional groups in Geneva http://www.itu.int/en/ITU-R/conferences/wrc/2015/irwsp/2015/Pages/program.aspx where item 1.14 will be covered on Thursday. There are 6 presentations of the preparations in powerpoint documents which are currently available there. In particular the one on http://www.itu.int/md/R15-WRC15PREPWORK-C-0008/en has a chart on page 13 which shows the currently known positions of the regional groups. There is no consensus. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m From brooks at edlmax.com Sat Aug 29 15:12:58 2015 From: brooks at edlmax.com (Brooks Harris) Date: Sat, 29 Aug 2015 15:12:58 -0400 Subject: [LEAPSECS] countdown to WRC-15 In-Reply-To: <20150829183213.GA25467@ucolick.org> References: <20150829183213.GA25467@ucolick.org> Message-ID: <55E2043A.3000908@edlmax.com> Thanks Steve, I was wondering what was going on (but lazily didn't go hunting). Did the question change? It seems like the current statement is more elaborate, if seemingly somewhat tangled, from earlier versions? ...LEAPSECS/ITU-R/R15-WRC15PREPWORK-C-0008!!PDF-E.pdf WRC-15 agenda item 1.14 Method A ? Remove the leap second insertion or deletion from the definition of UTC in order to make it become a continuous time-scale and either (A1) retain the name UTC or (A2) adopt a new name. Method B ? Keep the current definition of UTC, disseminate the UTC time-scale and also disseminate a continuous time-scale (TAI) on an equal basis. Method C ? Keep the current definition of UTC and enable the recovery of the International Atomic Time (TAI) (C1) or disseminate another continuous system timescale (C2). Method D ? No change Method (C1) seems like the choice to me, if by this they mean electronic dissemination of the Leap Seconds table in some useable form(s), the obvious missing link since 1972. -Brooks On 2015-08-29 02:32 PM, Steve Allen wrote: > Regional meetings continue about the fate of the leap second as > various bodies consider their position on WRC-15 Agenda Item 1.14. > http://www.itu.int/en/ITU-R/conferences/wrc/2015/Pages/reg-prep.aspx > shows that the Arab group just finished, and the European and Russian > meetings are still pending. > > Next week is one more meeting of all the regional groups in Geneva > http://www.itu.int/en/ITU-R/conferences/wrc/2015/irwsp/2015/Pages/program.aspx > where item 1.14 will be covered on Thursday. > > There are 6 presentations of the preparations in powerpoint documents > which are currently available there. In particular the one on > http://www.itu.int/md/R15-WRC15PREPWORK-C-0008/en > has a chart on page 13 which shows the currently known positions of > the regional groups. There is no consensus. > > -- > Steve Allen WGS-84 (GPS) > UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 > 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 > Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m > _______________________________________________ > LEAPSECS mailing list > LEAPSECS at leapsecond.com > https://pairlist6.pair.net/mailman/listinfo/leapsecs > > From stenn at ntp.org Sat Aug 29 15:49:10 2015 From: stenn at ntp.org (Harlan Stenn) Date: Sat, 29 Aug 2015 19:49:10 +0000 Subject: [LEAPSECS] countdown to WRC-15 In-Reply-To: Steve Allen's (sla@ucolick.org) message dated Sat, 29 Aug 2015 11:32:13. <20150829183213.GA25467@ucolick.org> Message-ID: I've not been able to follow these discussions. I look forward to the time when there's less pressure on my schedule. Has anybody put forth the following position: - The various current popular timescales are of significant value. - (a variety of points covering the "backstory", "foundation", and pros/cons of these timescales.) - If something doesn't happen "often enough" it's difficult for people who have to deal with these events to easily accomodate them. As a case in point, I offer full/proper handling of leap years in calendars. I submit this situation was not properly handled until 1) the internet made it easy to copy/paste code, and 2) Y2K got everybody looking at their date code. - So I propose that every N months' time, where N is 1-6, we schedule either an addition or a deletion of a leap second. In doing so, we make it "compelling" for leap seconds to be properly handled, and I submit that the "problem" of handling leap seconds will be resolved satisfactorily within 1-2 years' time. Are there significant additional costs to implementing this approach when compared to the costs of continuing to only address leap seconds as needed? I'm hesitant to have asked that, as it's akin to asking what the costs are to changing UTC so it doesn't have leap seconds. This is all about "how to lie with statistics", except that the scope is much smaller. I'll point out that a side issue is that there are HUGE number of ancient versions of NTP out there and too many folks are being slow to update. Dealing with leap second additions and deletions will be yet another incentive to upgrade this software. -- Harlan Stenn http://networktimefoundation.org - be a member! From tvb at LeapSecond.com Sun Aug 30 19:25:48 2015 From: tvb at LeapSecond.com (Tom Van Baak) Date: Sun, 30 Aug 2015 16:25:48 -0700 Subject: [LEAPSECS] countdown to WRC-15 References: Message-ID: Hi Harlan, Look back in the archives for LSEM (Leap Second Every Month) discussions. The idea was to have a leap second at the end of every month, always. It would force all precision timing systems to correctly deal with leap seconds, positive as well as negative. DUT1 would remain < 0.7 s. By sheer annoyance it would force the automation of the leap second notification infrastructure. A past record or future scheduling of leap seconds could be encoded into as little as 12-bits per year. LSEM would elevate leap seconds from unpredictable and rare to certain and common. Errors in software would be found within a month or two instead of many years. It would get rid of the awkward June/December convention, and track impending changes in Earth rotation 6x better. The next generation of school children would all know about leap seconds just like all children already know about leap years. It is compatible with WWVB and GPS and NTP and smearing algorithms. It would also solve a serious problem with UTC clocks today: not knowing if there is a leap second vs. knowing there is no leap second. The two states are currently indistinguishable but LSEM would allow you to know the difference. It replaces two unknowns (when is the next leap second and what sign will it be) with one unknown (what sign will it be this month). Of course the cost of LSEM would be prohibitive, but it's still an elegant idea on paper. /tvb ----- Original Message ----- From: "Harlan Stenn" To: "Leap Second Discussion List" Sent: Saturday, August 29, 2015 12:49 PM Subject: Re: [LEAPSECS] countdown to WRC-15 > I've not been able to follow these discussions. I look forward to the > time when there's less pressure on my schedule. > > Has anybody put forth the following position: > > - The various current popular timescales are of significant value. > > - (a variety of points covering the "backstory", "foundation", and > pros/cons of these timescales.) > > - If something doesn't happen "often enough" it's difficult for people > who have to deal with these events to easily accomodate them. As a > case in point, I offer full/proper handling of leap years in > calendars. I submit this situation was not properly handled until 1) > the internet made it easy to copy/paste code, and 2) Y2K got everybody > looking at their date code. > > - So I propose that every N months' time, where N is 1-6, we schedule > either an addition or a deletion of a leap second. In doing so, we > make it "compelling" for leap seconds to be properly handled, and I > submit that the "problem" of handling leap seconds will be resolved > satisfactorily within 1-2 years' time. > > Are there significant additional costs to implementing this approach > when compared to the costs of continuing to only address leap seconds as > needed? > > I'm hesitant to have asked that, as it's akin to asking what the costs > are to changing UTC so it doesn't have leap seconds. This is all about > "how to lie with statistics", except that the scope is much smaller. > > I'll point out that a side issue is that there are HUGE number of > ancient versions of NTP out there and too many folks are being slow to > update. Dealing with leap second additions and deletions will be yet > another incentive to upgrade this software. > > -- > Harlan Stenn > http://networktimefoundation.org - be a member! > _______________________________________________ > LEAPSECS mailing list > LEAPSECS at leapsecond.com > https://pairlist6.pair.net/mailman/listinfo/leapsecs