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    Re: Timekeeping in the post-WWV/post-HF world
    From: Robert VanderPol II
    Date: 2018 Sep 26, 05:20 -0700

    Did you fit a line to see if there was a seasonal variation?

    Re: Timekeeping in the post-WWV/post-HF world
    From: Roger W. Sinnott
    Date: 2018 Sep 25, 22:34 -0400

    I wrote an article for Sky & Telescope in June 1988, pages 658-661, entitled "A $6 Watch Beats Harrison's Chronometer."  The watch was made by Lorus and contained a quartz crystal and lithium battery.  After setting it once, in June 1984, I soon found that it gained about 1 second a week.  I made 127 checks against WWV over the next four years without ever resetting it.  No special effort was made to keep the watch at constant temperature, but I normally either wore it or kept it indoors.  The attached plot shows the results.

     

    The best-fitting straight line is a gaining rate of 50.4 seconds per year. When that rate is applied to the watch readings, the deduced time is always correct within 7 seconds.  Not bad!

     

    Roger

       
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