Table making in astronomy

Abstract

Throughout history, astronomers have studied the motions of the bodies of the solar system. In the second half of the 17th century, these studies took a monumental step forward with Isaac Newton's (1642–1727) formulation of the laws of motion and the principle of universal gravitation. The development of analytical mechanics in the 18th century opened the way for a complete treatment of all the gravitational effects produced within the solar system, as required to predict the motions of these bodies. Gravitational astronomers, who formulated equations of motion for the interactions of the planets, discovered that these equations could not be integrated in closed form, and developed approximation techniques for the successful integration of the equations. The history of predicting planetary positions using theories developed in celestial mechanics involved a search for a complete unified set of precepts for use in computing future planetary positions. This search was occasionally beset by related difficulties due to inadequacies in astronomers' planetary observations and understanding of planetary interactions. Therefore, it took almost 200 years after Newton to realize the goal. The drama has a cast of epic proportions and its denouement occurred at the beginning of the 20th century in Paris with a major assembly of astronomers at an international conference. This chapter examines some highlights in this history, namely, the search, the problem of seemingly unstablizing interactions, and the difficulties with observation, focusing on only a few of the principal actors and institutions. Primary emphasis in the chapter is on the first stage in the process of predicting future planetary positions, namely, preparation of precepts, rather than the following stage of computing predicted positions.