Celestial navigation includes finding your ships position at sea using various celestial bodies such as the sun, the moon, the planets and the stars. It does not imply navigation among the stars as you probably imagined.

While there are various modem electronic position finding systems provided on the ships now, none of them are fail-safe. Celestial navigation therefore remains the basic and unfailing mode of finding your position when at sea.

To obtain our position on the earth’s surface using celestial bodies, it is necessary to use the data relating to the accurately established Positions of the celestial bodies and to relate this to our position on the earth. Let us now establish the co-ordinates used in defining the position of celestial bodies.

In the concept of celestial navigation, we assume that all the heavenly bodies are plotted on a uniform sphere called the celestial sphere as if they are all at the same distance. (Remember, they are at vast differing distances from each other!) Their Positions on this celestial sphere are carefully calculated so that at any moment we can spot the Celestial body and use it to fix our position.