“A single principle leading up to a single calculation, following a form always the same, constitutes, according to my mind, the safeguard of the navigator.”—H. Bersier, Preface—" Conduite du Navire.”
Calculation of the altitude of an observed heavenly body constitutes nowadays the principal problem of modern navigation.
1 be altitude, combined with the azimuth at the same instant, together determine the position of the navigator. Whether this position will be approximate or exact, depends upon the fundamental methods employed in the solution of the problem.
Many authorities have attacked this question, and each one has given us his own method of finding the required solution, employing ways and means more or less simple and expeditious.
In order to arrive at an easy method, which should be at the same time short and accurate, we have confronted this problem by starting with the following premises:
1. Without changing the dead reckoning position.
2. Without logarithms or interpolations of any kind.
3. To find the altitude.