The Besselian Elements

Anybody who wants to calculate the course of a solar eclipse needs the so-called "Besselian Elements". These are a set of eight variables obtained from the ephemeris (astronomical data for positions) of the Sun and Moon.

This book provides the mathematical tools to compute the visibility conditions of an eclipse for any place on Earth, e.g. widths of the lunar shadow, contact times or magnitude. The formulae are an integral part of computer algorithms nowadays, however, only few really understand in detail what happens in a simulation. In addition to solar eclipses, the book deals with lunar eclipses and the tolerance limits for the occurrence of an obscuration. Sample calculations demonstrate the working method. It is a step-by-step guide to getting started with the basics of eclipse theory.