Re: [LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954
I was surprised to find phrases in the Lick web pages: "CCIR ignored the advice that astronomers " and "squelched astronomers who insisted that leap seconds would cause trouble". I realize their author is not the only person with a strong emotional bias, but even so I question the tone of these web pages because they are inconsistent with the following: 1. There was a progression in thought as technology advanced and atomic clocks proved their reliability. 2. It should be obvious that ephemeris time would need a flywheel system to get practical time to the users, and GMT could be part of that. Today individual labs realize UTC(k) for the same reason - to flywheel before the monthly computations of UTC are published. WWVB, GPS, and your local cell towers are all part of the system as well. (Even so, I think everyone today agrees that Ephemeris time was a mistake.) 3. According to references in Nelson et al’s Metrologia article, which was peer-reviewed, it looks to me like the switch to UTC was by universal agreement among the institutions. The IAU, URSI, CIPM(=CGPM), and CCIR(= ITU) all agreed to the current system in the late 60's, and I would guess that the timing of their resolutions probably depended more on the (generally) 3-year spacing of their general assemblies than anything else. Note that many of those groups had overlapping membership. It would however be unusual if all individual members of these bodies ever agreed to any resolution, even if passed "by consensus". For more trivia, the dynamic Gernot Winkler of the USNO was both a practical clock man and astronomer. He was not the only one, and he was a very active member of the IAU who chaired commissions, served on working groups, etc. He told me personally that he and Essen independently came up with the idea of leap seconds. He also said a big reason was to win the support of the mariners, who in the pre-GNSS days actually did celestial navigation and who in the pre-internet days could not easily get access to tables that incorporated the difference between UT1 and UTC. From: LEAPSECS [leapsecs-boun...@leapsecond.com] on behalf of Steve Allen [s...@ucolick.org] Sent: Wednesday, March 14, 2018 12:16 AM To: Leap Second Discussion List Subject: [Non-DoD Source] [LEAPSECS] D.H. Sadler in 1954 In 1954 D.H. Sadler produced a monograph on the changes in time that had been resolved at the 1952 IAU General Assembly. His writeup is clearer than almost anything else for the next 60 years. It was published in Occasional Notices of the RAS, and it has been hard to find until now. https://www.ucolick.org/~sla/leapsecs/twokindsoftime.html This is one of the series of documents produced starting in 1948 and proceeding through the next 20 years where astronomers explained that two kinds of time would be needed to satisfy all applications. -- Steve Allen 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 http://www.ucolick.org/~sla/ Hgt +250 m ___ 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
Re: [LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954
On Fri, Mar 16, 2018 at 10:16 AM, Matsakis, Demetrios N CIV NAVOBSY, N3TS < demetrios.matsa...@navy.mil> wrote: > I was surprised to find phrases in the Lick web pages: "CCIR ignored the > advice that astronomers " and "squelched astronomers who insisted that leap > seconds would cause trouble". > > I realize their author is not the only person with a strong emotional > bias, but even so I question the tone of these web pages because they are > inconsistent with the following: > > 1. There was a progression in thought as technology advanced and atomic > clocks proved their reliability. > > 2. It should be obvious that ephemeris time would need a flywheel system > to get practical time to the users, and GMT could be part of that. Today > individual labs realize UTC(k) for the same reason - to flywheel before the > monthly computations of UTC are published. WWVB, GPS, and your local cell > towers are all part of the system as well. (Even so, I think everyone > today agrees that Ephemeris time was a mistake.) > > 3. According to references in Nelson et al’s Metrologia article, which > was peer-reviewed, it looks to me like the switch to UTC was by universal > agreement among the institutions. The IAU, URSI, CIPM(=CGPM), and CCIR(= > ITU) all agreed to the current system in the late 60's, and I would guess > that the timing of their resolutions probably depended more on the > (generally) 3-year spacing of their general assemblies than anything else. > Note that many of those groups had overlapping membership. It would > however be unusual if all individual members of these bodies ever agreed to > any resolution, even if passed "by consensus". > The adaptation of UTC was by consensus. The leap second stuff was a rush job in 1971 with the first leap second on Jan 1, 1972. I think that rush job is what the Lick pages refer to. For more trivia, the dynamic Gernot Winkler of the USNO was both a > practical clock man and astronomer. He was not the only one, and he was a > very active member of the IAU who chaired commissions, served on working > groups, etc. He told me personally that he and Essen independently came up > with the idea of leap seconds. He also said a big reason was to win the > support of the mariners, who in the pre-GNSS days actually did celestial > navigation and who in the pre-internet days could not easily get access to > tables that incorporated the difference between UT1 and UTC. > UT1 - UTC was known to .1s based on WWV and other broadcasts. At the time, the < 1s error was so that you limited your error in navigation to something acceptable. Though one also had LORAN-C (which had it's own time-scale based on UTC w/o leapseconds to compute the TOCs, but whose operational bases had atomic clocks set to UTC). Warner > To: Leap Second Discussion List > Subject: [Non-DoD Source] [LEAPSECS] D.H. Sadler in 1954 > > In 1954 D.H. Sadler produced a monograph on the changes in time > that had been resolved at the 1952 IAU General Assembly. > His writeup is clearer than almost anything else for the next 60 years. > It was published in Occasional Notices of the RAS, and it has been hard > to find until now. > https://www.ucolick.org/~sla/leapsecs/twokindsoftime.html > This is one of the series of documents produced starting in 1948 and > proceeding through the next 20 years where astronomers explained that > two kinds of time would be needed to satisfy all applications. > > -- > Steve Allen 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 http://www.ucolick.org/~sla/ Hgt +250 m > ___ > 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 > ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954
On Fri 2018-03-16T16:16:23+ Matsakis, Demetrios N CIV NAVOBSY, N3TS hath writ: > I was surprised to find phrases in the Lick web pages: "CCIR ignored > the advice that astronomers " and "squelched astronomers who insisted > that leap seconds would cause trouble". The IAU publications around the 1970 General Assembly say that. > GPS, and your local cell towers are all part of the system as well. One need merely ask everyone with a 4G Android phone in southern Tasmania whose phone clocks were all an hour off Friday. http://www.abc.net.au/news/2018-03-16/time-glitch-leaves-some-hobart-residents-an-hour-late/9554758 http://www.dailymail.co.uk/news/article-5508199/Tasmanians-hit-Telstra-phone-glitch-shifted-clocks-back.html > it looks to me like the switch to UTC was by universal agreement > among the institutions. The IAU, URSI, CIPM(=CGPM), and CCIR(= ITU) > all agreed to the current system in the late 60's, and I would guess > that the timing of their resolutions probably depended more on the > (generally) 3-year spacing of their general assemblies than anything > else. Note that many of those groups had overlapping membership. It > would however be unusual if all individual members of these bodies > ever agreed to any resolution, even if passed "by consensus". It looks like some paragraphs about lack of agreement were elided from the transcriptions of the 1970 IAU General Assembly, but many words remain that speak of serious disagreeing, ignoring, and excluding. > For more trivia, the dynamic Gernot Winkler of the USNO was both a > practical clock man and astronomer. He was not the only one, and he > was a very active member of the IAU who chaired commissions, served on > working groups, etc. He told me personally that he and Essen > independently came up with the idea of leap seconds. I am going to have to stop being amazed when I keep learning of yet another person taking credit for inventing the leap second. The 1970 IAU documents indicate that Winkler was one who warned that leap seconds would cause trouble for automated systems. They also make it clear that there was not unanimity, and that there was overlap. The rest of this is nitty gritty details and references with links to original content so folks can read that. The documents from the 1970 IAU meeting tell a story which was witnessed by LEAPSECS contributor Clive Page leaving enough impression for that to be in his contribution to an art video https://www.youtube.com/watch?v=GtYvSjS1jUI&t=4m24s Transactions of the IAU A (1970) (prior to the General Assembly) Report to Comm 31 http://adsabs.harvard.edu/abs/1970IAUTA..14..343Z President: F. Zagar Vice-president: G.M.R. Winkler Winkler was V.P., and acting president at the General Assembly, yet the tone of this report to Comm 31 is clearly not in accord with the actions of the radio broadcast and metrology agencies. bottom of p.344, the CGPM ignored the 1967 IAU recommendations and triggered intervention by the IAU president. middle of p.345, Sadler and Winkler are cited pointing out that an aircraft Collision Avoidance System cannot tolerate time steps. Also this sentence has been ignored: It is stated as a necessity that activities concering time service should be completely independent of the activities of frequency laboratories. bottom of p.345, in 1969 the PTB and URSI asked for a Consultative Committee on Time Scales to consider the course of action, and CCIR working party 7 ignored them. (My impression is that the BIPM/CCTF Task Group on Time Scale Definitions (TGTSD) which first met in 2016 means that this request was deferred for 47 years.) Transactions of the IAU B (1971) (at the General Assembly) Report of Comm 4 http://adsabs.harvard.edu/abs/1971IAUTB..14...79W p.80, H.M.Smith reported that the CCIR had instituted the leap second, and D.H.Sadler was strongly opposed. Also, the IAU had not been officially informed of the CCIR action to create the leap second. (The proceedings of the CCIR meetings through 1980 indicate that H.M.Smith spearheaded the effort to get international agencies and national laws to adopt the leap second as the perfect solution.) Report of Comm 31 http://adsabs.harvard.edu/abs/1971IAUTB..14..193W with last page of that included within Report of Joint meeting of Comms 4 and 31 http://adsabs.harvard.edu/abs/1971IAUTB..14..198W Winkler was acting president at these meetings. p.194 has a break in the flow. Paragraphs about the perennial underfunding of the BIH are inexplicably followed by The President urged Commission 31 to consider the scope of its activities. and the next paragraph inexplicably switches to H.M.Smith talking about problems of two time systems. The second session invited BIPM president J.Terrien to talk about atomic time scales, something that he followed up later Metrologia, v8, #3, p.99 (1972) http://iopscience.iop.org/article/10.1088/0026-1394/8/3/004 in the last few years regrettable m
Re: [LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954
On 2018-03-17 19:02, Steve Allen wrote: I am going to have to stop being amazed when I keep learning of yet another person taking credit for inventing the leap second. The 1970 IAU documents indicate that Winkler was one who warned that leap seconds would cause trouble for automated systems. They also make it clear that there was not unanimity, and that there was overlap. [McCarthy 2009. p 228] states that leap seconds in UTC was an idea "introduced independently by Louis Essen and Gernot Winkler". It just was a variation of "Stepped Atomic Time" (SAT) that had gained some usage at the time, and was known to be practicable. Regardless of the amount of disagreement among astronomers then, there certainly seems to be some _current_ disagreement among astronomers about the future of UTC -- should leap seconds be omitted in the future so that UTC becomes a continuous time scale, or should we keep the current limit of |UT1 - UTC|? The current proposal [BIPM 2018. p 11..13, 32..33] for Resolution B of the General Conference of Weights and Measures 2018 makes UTC a time scale "produced by the BIPM" and recommends a revision of the limit |UT1 - UTC|. While the proposed Resolution does recommend work on improved dissemination of UT1 - UTC, it does not say anything about the dissemination of TAI - UTC. So, the likely future is that the limit on |UT1 - UTC| will be dropped, leap seconds will no longer be applied, and UTC will become a fixed translate of TAI (so that dissemination of TAI - UTC becomes unnecessary). Hence, people [astronomers?] interested in keeping the current definition of UTC should strive for improved dissemination of TAI - UTC, so as to make a continuous time scale easily accessible (for example, together with NTP time signals). The knowledge of current UTC, as a compromise between TAI and UT1, is, in the long term, obviously of less value than the knowledge of both UT1 and TAI together; the short term advantage of using UTC may only lie in the fact that it may be easier to newly disseminate TAI - UTC with UTC values than to extend the dissemniation of UTC to values of UT1 - UTC exceeding 1 s. [BIPM 2018] CGPM26 convocation: draft Resolution B [https://www.bipm.org/utils/en/pdf/CGPM/Convocation-2018.pdf] [McCarthy 2009] Dennis D McCarthy, P Kenneth Seidelmann: "Time -- From Earth Rotation to Atomic Physics". Wiley-VCH Verlag. 2009 Weinheim. ISBN 978-3-527-40780-4. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954
On 2018-03-17 06:52 PM, Michael.Deckers via LEAPSECS wrote: [BIPM 2018] CGPM26 convocation: draft Resolution B [https://www.bipm.org/utils/en/pdf/CGPM/Convocation-2018.pdf] DocTranslator did a nice (free) job of translating this pdf to English - A) Download to your local drive B) Drag to DocTranslator C) Double check the source language - it didn't detect the French D) It will ask you to save the result to your local drive DocTranslator https://www.onlinedoctranslator.com/ -Brooks [McCarthy 2009] Dennis D McCarthy, P Kenneth Seidelmann: "Time -- From Earth Rotation to Atomic Physics". Wiley-VCH Verlag. 2009 Weinheim. ISBN 978-3-527-40780-4. Michael Deckers. ___ 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
Re: [LEAPSECS] [Non-DoD Source] D.H. Sadler in 1954
On 2018-03-17 23:34, Brooks Harris wrote: DocTranslator did a nice (free) job of translating this pdf to English - A) Download to your local drive B) Drag to DocTranslator C) Double check the source language - it didn't detect the French D) It will ask you to save the result to your local drive DocTranslator https://www.onlinedoctranslator.com/ Thanks for the hint! Actually, I should have mentioned that the document [https://www.bipm.org/utils/en/pdf/CGPM/Convocation-2018.pdf] contains the English version after the French text, so there is no need to use an automated translator to English. And the BIPM always stress the fact that the French version is the definitive one, parbleu. Michael Deckers. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
