Jim, It is my understanding that the government standard offices around the globe, like NIST, calculates time by the earths rotation, I guess you could say, the old way, or using astronomy, but with this, they use things like the decay factors of atomic materials to keep this time. If I recall, things had to be recallibrated after the earthquake at Japan, as it changed the earths rotational speed a very minute amount. Its kind of like, which came first, the chicken or the egg on the standards.
Best, Will *********** REPLY SEPARATOR *********** On 7/14/2011 at 12:26 PM Jim Palfreyman wrote: >Hi All, > >I've just realised I don't understand something. Something quite basic. > >Primary Standards are ones which don't have to be calibrated against others. >My understanding is that Caesium and Hydrogen masers are Primary Standards >(in our field). > >Secondary Standards are calibrated against the Primary Standards. My >understanding is that Rubidium is an example of a Secondary Standard. > >So I can calibrate my Rubidium clocks by adjusting the C Field. All good. > >But why is it that Caesium Clocks and Hydrogen Masers have an adjustment >facility? > >And what about the clocks used to determine UTC around the world? Do they >have an adjustment facility? What are they adjusted to? Wouldn't that make >them Secondary Standards? > >Now I'm aware that the "average" of those clocks is UTC, so are those clocks >adjusted regularly to get closer to that average? > >I'm sure someone can clear this up for me. > >Regards, > >Jim >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET Smart Security, version of virus signature database 5851 (20110206) __________ > >The message was checked by ESET Smart Security. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
