A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
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!