The history of the asteroids really starts before they were discovered. Their existence was first suspected as a result of the discovery of ""Bode's Law"" as it was called: a relation between the mean distances of the planets from the Sun.
Before we can appreciate what orbit computing involves, we first require the answers to the questions: (1) What is the form of the orbit of a planet round the Sun? (2) How does the planet move in that orbit? The answers to these questions were given long ago by Kepler, who foundthat: (1) The planet moves always in one and the same plane which passes through the Sun. (2) The path in that plane is an ellipse with the Sun in one focus. (3) It moves so that the line joining the planet to the Sun sweeps out equal areas in equal times. An eclipse is a curve such that the sum of the distances of a point moving along it from two fixed points remains constant. The two fixed points are called the foci.