On Jan 21, 2011, at 5:05 PM, Phillip Hallam-Baker wrote: > GMT still exists as a legal construct and could well prove useful since it is > ultimately under control of HMG, quite possibly it can be modified by as > little as an order in council. > > So if HMG would eliminate the inanity of leap seconds in GMT we could > probably move most computer systems back to GMT rather than UTC as a > reference point. > > > The idea that there is utility in leap seconds is ridiculous. Most > astronomers I have talked to tell me that UTC is useless for their purposes > anyway and the time of mid-day varies at Greenwich by 5 minutes over the > course of a year so what does it matter which two days are right? >
UTC is kept close to UT1 for celestial navigation, not astronomy, and is indeed somewhat archaic. (The idea was that you could use UTC, i.e., civil time, as reported by a simple radio, and then do celestial navigation to get within about 1 km of your true location. You still can, but that is of less and less utility as navigation moves to GPS and time keeping becomes ever better.) The time of mid-day is solar time, which does vary in a periodic fashion during the year, driven by the Earth's orbital motion. These variations are not shared by mean solar time, which is now-a-days really an atomic time. Regards Marshall > > On Fri, Jan 21, 2011 at 3:56 PM, Marshall Eubanks <[email protected]> wrote: > > On Jan 21, 2011, at 3:48 PM, Clint Chaplin wrote: > > > Hey, Paris lobbied heavily to have the Prime Meridian be fixed in Paris. > > That would have really made them the center of the navigational world. > > > > Yes, and then they got the BIH, which got them the power to change GMT to > UTC. (GMT no longer has any official existence.) > > Marshall > > > On Fri, Jan 21, 2011 at 12:37 PM, todd glassey <[email protected]> > > wrote: > > On 1/21/2011 10:22 AM, Phillip Hallam-Baker wrote: > >> On Fri, Jan 21, 2011 at 11:10 AM, Ole Jacobsen <[email protected]> wrote: > >> > >> Does anyone see the irony of us even discussing concerns about, of all > >> things, FOOD when it comes to Paris? > >> > >> What else is there to discuss in Paris? > >> > > Making Paris the center of the world - ever look at French Navigation > > Charts - relative to Admiralty charts from any other nation? > > > > Todd > > > >> > >> > >> -- > >> Website: http://hallambaker.com/ > >> > >> > >> > >> _______________________________________________ > >> Ietf mailing list > >> > >> [email protected] > >> https://www.ietf.org/mailman/listinfo/ietf > >> > >> > >> No virus found in this message. > >> Checked by AVG - www.avg.com > >> Version: 10.0.1191 / Virus Database: 1435/3394 - Release Date: 01/21/11 > >> > > > > > > _______________________________________________ > > Ietf mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/ietf > > > > > > > > > > -- > > Clint (JOATMON) Chaplin > > Principal Engineer > > Corporate Standardization (US) > > SISA > > _______________________________________________ > > Ietf mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/ietf > > _______________________________________________ > Ietf mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ietf > > > > -- > Website: http://hallambaker.com/ > _______________________________________________ Ietf mailing list [email protected] https://www.ietf.org/mailman/listinfo/ietf
