Fotheringham’s 1920 Accelerations of the Sun and Moon Revisited

Abstract

One hundred years ago, J.K. Fotheringham famously derived the “accelerations” of the Sun and Moon from the reports of 11 classical solar eclipses. We review critically the reliability of these eclipse reports and rework his diagrammatic method, treating the deceleration of the Earth’s rotation as an unknown, rather than the “acceleration” of the Sun. There is some serendipity in his choice of the critical eclipses, which opportunely facilitated his derivation of seemingly accurate results for the accelerations.