I may be missing something. Should there be any reason that TT-UT1 will change? Ronald
On 11/20/22, leapsecs-requ...@leapsecond.com <leapsecs-requ...@leapsecond.com> wrote: > Send LEAPSECS mailing list submissions to > leapsecs@leapsecond.com is changed? > > To subscribe or unsubscribe via the World Wide Web, visit > https://pairlist6.pair.net/mailman/listinfo/leapsecs > or, via email, send a message with subject or body 'help' to > leapsecs-requ...@leapsecond.com > > You can reach the person managing the list at > leapsecs-ow...@leapsecond.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of LEAPSECS digest..." > > > Today's Topics: > > 1. Re: future access to solar time? (Tony Finch) > 2. Re: Global timekeepers vote to scrap leap second by 2035 > (Steve Allen) > 3. Re: future access to solar time? > (Seaman, Robert Lewis - (rseaman)) > 4. Re: future access to solar time? (Kevin Birth) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 20 Nov 2022 15:15:42 +0000 > From: Tony Finch <d...@dotat.at> > To: Leap Second Discussion List <leapsecs@leapsecond.com> > Subject: Re: [LEAPSECS] future access to solar time? > Message-ID: <a1902489-ea04-abcd-a14e-576e45b10...@dotat.at> > Content-Type: text/plain; charset=US-ASCII > > Seaman, Robert Lewis - (rseaman) <rsea...@arizona.edu> wrote: >> >> The plan, rather, is to cease easy access to solar time. > > The resolution says the GCPM > > : encourages the BIPM to work with relevant organizations to identify the > : need for updates in the different services that disseminate the value of > : the difference (UT1-UTC) and to ensure the correct understanding and use > : of the new maximum value. > > So I think your summary is a bit off the mark. > > I guess the ITU is going to revise TF.460 to allow larger values of DUT1 > in time signals, and MSF etc. will accommodate the change too. (Do any of > the national broadcast signals actually follow the ITU spec?) > > GPS L5 signals provide UT1 as an 8.23 bits two's complement fixed point > difference from GPS time. This is enough to cope with the changes in the > CGPM resolution. See IS-GPS-705 p. 87 at > https://www.gps.gov/technical/icwg/ > > I have not been able to find any specs for NMEA sentences that contain > anything like UT1 or DUT1 or delta-T, but I expect they will be created > before too long, as more GPS receivers support L5 signals. > > And there are other sources of UT1 like NIST's stunt NTP servers. > > -- > Tony Finch <d...@dotat.at> https://dotat.at/ > East Sole, Lundy, Fastnet: Westerly backing southerly, 5 to 7, then > becoming cyclonic 7 to severe gale 9 later, perhaps storm 10 later. > Rough or very rough, becoming very rough or high later. Rain or > showers. Good, occasionally poor. > > > ------------------------------ > > Message: 2 > Date: Sun, 20 Nov 2022 07:49:08 -0800 > From: Steve Allen <s...@ucolick.org> > To: Leap Second Discussion List <leapsecs@leapsecond.com> > Subject: Re: [LEAPSECS] Global timekeepers vote to scrap leap second > by 2035 > Message-ID: <20221120154908.ga7...@ucolick.org> > Content-Type: text/plain; charset=utf-8 > > On Sun 2022-11-20T13:23:32+0000 Kevin Birth hath writ: >> As far as I can tell, they were never successful, but it did keep them >> busy. > > As Rod Serling wrote in The Big Tall Wish > You got to believe, Bolie. > But worse, because in this arena infidels will not be tolerated. > > -- > Steve Allen <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 > > > ------------------------------ > > Message: 3 > Date: Sun, 20 Nov 2022 15:54:37 +0000 > From: "Seaman, Robert Lewis - (rseaman)" <rsea...@arizona.edu> > To: Leap Second Discussion List <leapsecs@leapsecond.com> > Subject: Re: [LEAPSECS] future access to solar time? > Message-ID: > > <byapr19mb22638de508e6b96fa8c934e6a7...@byapr19mb2263.namprd19.prod.outlook.com> > > Content-Type: text/plain; charset="windows-1252" > > Hi Tony, > > Getting the solar time currently means looking at your watch or the upper > right-hand corner of the monitor. Would anybody else?s summary of the notion > of ?easy access? include phrases like: ?8.23 bits two?s complement fixed > point? or ?NMEA sentences that contain anything like UT1 or DUT1 or > delta-T?? > > I have been presuming tenth-second DUT1 values are slated for demolition > with leap seconds. Can anybody confirm differently? I applaud the goal of > ensuring understanding and usage of whatever infrastructure will exist. Few > systems currently use DUT1. One of the issues is that many more will need to > start. > > UT1 itself is only known retroactively. If your use of the word ?stunt? > wasn?t a typo, it seems to me that NIST rather needs robust and easy-to-use > infrastructure. I was never able to get reliable access to the UT1 NTP > server, and generally, our group doesn?t build reliance on third-party NTP > pools into our operational systems. > > We should all welcome GNSS support for access to UT1 (or a coherent > variation known in advance), but as you suggest this will require new > infrastructure and standards. Perhaps I?m off the mark, but that most > definitely doesn?t imply anybody else has yet found the mark themselves. > > Rob > > > Seaman, Robert Lewis - (rseaman) <rsea...@arizona.edu> wrote: > >> The plan, rather, is to cease easy access to solar time. > > The resolution says the GCPM > > : encourages the BIPM to work with relevant organizations to identify the > : need for updates in the different services that disseminate the value of > : the difference (UT1-UTC) and to ensure the correct understanding and use > : of the new maximum value. > > So I think your summary is a bit off the mark. > > I guess the ITU is going to revise TF.460 to allow larger values of DUT1 > in time signals, and MSF etc. will accommodate the change too. (Do any of > the national broadcast signals actually follow the ITU spec?) > > GPS L5 signals provide UT1 as an 8.23 bits two's complement fixed point > difference from GPS time. This is enough to cope with the changes in the > CGPM resolution. See IS-GPS-705 p. 87 at > https://www.gps.gov/technical/icwg/ > > I have not been able to find any specs for NMEA sentences that contain > anything like UT1 or DUT1 or delta-T, but I expect they will be created > before too long, as more GPS receivers support L5 signals. > > And there are other sources of UT1 like NIST's stunt NTP servers. > > -- > Tony Finch <d...@dotat.at> https://dotat.at/ > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <https://pairlist6.pair.net/pipermail/leapsecs/attachments/20221120/ae28a717/attachment-0001.htm> > > ------------------------------ > > Message: 4 > Date: Sun, 20 Nov 2022 16:14:55 +0000 > From: Kevin Birth <kevin.bi...@qc.cuny.edu> > To: Leap Second Discussion List <leapsecs@leapsecond.com> > Subject: Re: [LEAPSECS] future access to solar time? > Message-ID: > > <bl1pr14mb5077db5d8dedfde3f2dc014ba9...@bl1pr14mb5077.namprd14.prod.outlook.com> > > Content-Type: text/plain; charset="us-ascii" > > As important as UT1 is in astrology, look to South Asia/East Asia for a > solution to this problem. It is also important in the determination of > Jewish and Islamic prayer times. > > Many existing apps that provide these services rely on UTC as a rough > representation of UT1, but if UTC drifts from UT1 by more than 1 second, > they will develop new ways to handle that difference. > > I expect there will be a proliferation of updated apps, some of which are > tied to various national observatories, that will compete in the offering of > some form of UT1 or DUT1 that could then be related to UTC on local systems. > But given the importance of UT1 to many people, I will be curious to see if > some nations set up their own time synchronization protocols to disseminate > UT1. Between China and India, there's a large enough market for this. > > Cheers, > > Kevin > > > > > > > > > ------------------ > "Time is the measure of a wobbly world, and things slipping away." > Rabanus Maurus, 9th century. > > Kevin K. Birth > Department of Anthropology > Queens College, CUNY > Flushing, NY 11367 > From: LEAPSECS <leapsecs-boun...@leapsecond.com> On Behalf Of Seaman, Robert > Lewis - (rseaman) > Sent: Sunday, November 20, 2022 10:55 AM > To: Leap Second Discussion List <leapsecs@leapsecond.com> > Subject: Re: [LEAPSECS] future access to solar time? > > Hi Tony, > > Getting the solar time currently means looking at your watch or the upper > right-hand corner of the monitor. Would anybody else's summary of the notion > of "easy access" include phrases like: "8.23 bits two's complement fixed > point" or "NMEA sentences that contain anything like UT1 or DUT1 or > delta-T"? > > I have been presuming tenth-second DUT1 values are slated for demolition > with leap seconds. Can anybody confirm differently? I applaud the goal of > ensuring understanding and usage of whatever infrastructure will exist. Few > systems currently use DUT1. One of the issues is that many more will need to > start. > > UT1 itself is only known retroactively. If your use of the word "stunt" > wasn't a typo, it seems to me that NIST rather needs robust and easy-to-use > infrastructure. I was never able to get reliable access to the UT1 NTP > server, and generally, our group doesn't build reliance on third-party NTP > pools into our operational systems. > > We should all welcome GNSS support for access to UT1 (or a coherent > variation known in advance), but as you suggest this will require new > infrastructure and standards. Perhaps I'm off the mark, but that most > definitely doesn't imply anybody else has yet found the mark themselves. > > Rob > > > Seaman, Robert Lewis - (rseaman) > <rsea...@arizona.edu<mailto:rsea...@arizona.edu>> wrote: > >> The plan, rather, is to cease easy access to solar time. > > The resolution says the GCPM > > : encourages the BIPM to work with relevant organizations to identify the > : need for updates in the different services that disseminate the value of > : the difference (UT1-UTC) and to ensure the correct understanding and use > : of the new maximum value. > > So I think your summary is a bit off the mark. > > I guess the ITU is going to revise TF.460 to allow larger values of DUT1 > in time signals, and MSF etc. will accommodate the change too. (Do any of > the national broadcast signals actually follow the ITU spec?) > > GPS L5 signals provide UT1 as an 8.23 bits two's complement fixed point > difference from GPS time. This is enough to cope with the changes in the > CGPM resolution. See IS-GPS-705 p. 87 at > https://www.gps.gov/technical/icwg/<https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.gps.gov%2Ftechnical%2Ficwg%2F&data=05%7C01%7Ckevin.birth%40qc.cuny.edu%7C0032e12a552a4f38e1e908dacb0f94e9%7C6f60f0b35f064e099715989dba8cc7d8%7C0%7C0%7C638045565490819930%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=UkI6Nr1O%2FtHAf4Hx3f32qFwzA58K6r%2B3TrK8MQL%2BCvc%3D&reserved=0> > > I have not been able to find any specs for NMEA sentences that contain > anything like UT1 or DUT1 or delta-T, but I expect they will be created > before too long, as more GPS receivers support L5 signals. > > And there are other sources of UT1 like NIST's stunt NTP servers. > > -- > Tony Finch <d...@dotat.at<mailto:d...@dotat.at>> > https://dotat.at/<https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdotat.at%2F&data=05%7C01%7Ckevin.birth%40qc.cuny.edu%7C0032e12a552a4f38e1e908dacb0f94e9%7C6f60f0b35f064e099715989dba8cc7d8%7C0%7C0%7C638045565490819930%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rW6Z4%2F9joFauwpFzsMmi24ULV3S8HcfEKkSC%2FAffO98%3D&reserved=0> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <https://pairlist6.pair.net/pipermail/leapsecs/attachments/20221120/4fc09c84/attachment.htm> > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > LEAPSECS mailing list > LEAPSECS@leapsecond.com > https://pairlist6.pair.net/mailman/listinfo/leapsecs > > > ------------------------------ > > End of LEAPSECS Digest, Vol 172, Issue 9 > **************************************** > _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
