Tidal Gravity Variations Measured by a Fedchenko AChF-3 Precise Pendulum Clock

This dataset consists of 6 months (3 months in the fall of 1968 and in the fall of 1969) of the fractional frequency error of a Fedchenko AChF-3 Precise Pendulum Clock. The frequency of the pendulum varies with the value of the gravitational acceleration, and for this system the stability of the pendulum is such that tidal variations in gravity are visible. The readme file describes the source of the data and the file formats in more detail. A full discussion of these data is available in

D. C. Agnew (2020), Time and Tide: Pendulum Clocks and Gravity Tides, History of Geo- and Space Sciences, 11, in press.