OK I have learned a lot and absolutely fantastic news. No matter what my aged CS says I can claim its accurate now. Its simply the world has not caught up to or slowed down to it. Regards Paul
On Fri, May 11, 2012 at 2:30 AM, mike cook <michael.c...@sfr.fr> wrote: > Le 11/05/2012 07:14, Peter Monta a écrit : > > Are there better estimates of the ET second nowadays (relative to the >> SI second)? It would be interesting to know what the cesium frequency >> "should have been" if much better estimates of the ephemeris-time >> second were available at the time. One would think that with all the >> solar-system data JPL and others have had at their disposal since the >> 1970s, a very good ET-second number could be cooked up; better than >> 1950s Moon cameras at any rate. >> > > There are various refs in the pedia to later estimates. Markowitz (1988) > calculated an agreement to 1x10-10. but looking at the article I see there > were still some uncertainty in terms used to calculate ET and depending on > what was chosen gave 2x10-11 . Accordingly he concludes conservatively > that ET has been equal to Si within 1x10-9. > The uncertainties will have been reduced since then but not eliminated and > so "should have been" is a moving target but it would appear from the > above that the chosen SI value would still be preferred if the decision was > to be reappraised. > > > > ______________________________**_________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.