フリードリヒ・ヴィルヘルム・ベッセル
Repeatedly timing each period of a Kater pendulum, and adjusting the weights until they were equal, was time-consuming and error-prone. Friedrich Bessel showed in 1826 that this was unnecessary. As long as the periods measured from each pivot, T1 and T2, are close in value, the period "T" of the equivalent simple pendulum can be calculated from them: