>> Yes, others working with pendulums have also discovered that they end >> up making crude thermometers, barometers, or seismometers instead of a >> good clock. Still, not a reason to give up. But you know you have a >> world-class pendulum clock when, after having solved every other >> perturbation, you can see the effects of lunar tides in your data (as >> your good pendulum clock demonstrates it is also a fair gravimeter). > > That seems like a neat threshold. Are current pendulum clocks good enough to > notice tides? When was the first published paper? If not, how close?
Yes, it is a neat benchmark. Not a few modern clock makers have tried to reproduce or improve on the old masters. It turns out a pendulum clock needs to be accurate (stable) to 1e-7 or 1e-8 for tau from an hour to a day in order for it to "detect" tides. See this article I wrote a while back on the subject: Lunar/Solar Tides and Pendulum Clocks (part 1) http://www.leapsecond.com/hsn2006/ch1.htm Not sure what you mean by "current" pendulum clocks. I think modern commercial pendulum clocks are nowhere as accurate as the state-of-the-art pendulum clocks of the 1920's. Quartz clocks in the 30's and atomic clocks in the 50's put an end to the market for ultra precise pendulum clocks. /tvb _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts