); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] > Thank you all for your replies. It still begs the question of why > NIST and PTB disagree by nearly 5 Hz on their web pages - I'll write > and ask them, and report back what they say. > > Regards, > > Peter Vince (G8ZZR, London)
Peter, Yes, please send a note to NIST and have them update the Rb hyperfine frequency that appears in: http://tf.nist.gov/general/enc-re.htm#rubidiumoscillator My guess is the old ...608 number came from a 1959 paper: Hyperfine Transitions in Rubidium-87 Vapor http://tf.nist.gov/timefreq/general/pdf/1537.pdf I suggest for the purposes of their glossary, the new number doesn't have to be accurate to the micro-Hertz and probably doesn't need to be changed every time someone does a new experiment with Rb. NIST gives the defined value for Cesium: 9,192,631,770 Hz and a rounded value for Hydrogen: 1,420,405,752 Hz, so a value of 6,384,682,612 Hz might do. Not sure what to say about ...612.8 vs. ...610.904. Let NIST figure that one out. Either way, I don't have to change my cars ;-) http://www.leapsecond.com/pages/unix/ /tvb _______________________________________________ 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.
