[LEAPSECS] 2 meetings on UTC and the impending ITU-R RA vote

Tony Finch dot at dotat.at
Tue Jul 12 06:36:49 EDT 2011

Michael Deckers <michael.deckers at yahoo.com> wrote:


> But ephemeris time was deduced from astronomical observations of the

> Moon, not from quartz clocks.

Thanks for the clarifications. I wanted to emphasize that during the
"short reign of ephemeris time" reference clocks were not corrected by
observations of earth orientation, or at least that was not how the most
accurate corrections were made. And that quartz clocks were more stable
than observations of earth orientation but not more stable than
observations of the moon. Quartz clocks have problems with their frequency
changing as they age, and it took oo damn long to get frequency
corrections from the moon :-)

f.anthony.n.finch <dot at dotat.at> http://dotat.at/
Malin: Variable 3 or 4. Slight or moderate. Mainly fair. Good.

More information about the LEAPSECS mailing list