Celestial Navigation:
Navigation using the Stars
Celestial navigation is basically the art of navigating using the sun and the stars. Obviously you can only use the sun during the day, and the stars at night.
Celestial navigation at night is navigating using the stars. The moon can also be used but is not so accurate.
Which constellations to use will depend on whether you are in the northern hemisphere or the southern hemisphere.
Northern Hemisphere
In the Northern hemisphere the constellation to remember is Ursa Major. You use this constellation to find the pole star Polaris (also known as the North Star).
Actually, we are only interested in part of Ursa Major, the most easily spotted bit of it.
Most people know the Big Dipper, also known as the Plough in the UK.
It is probably the most recognizable pattern of stars in the northern sky.
A lot of people seem to think Polaris is the brightest star in the sky, but this is not true. In fact it is only average brightness (its about the 48th brightest star).
Polaris (the pole star) is part of the Little Dipper.
The Little Dipper looks very similar to the Big Dipper, but is harder to see because the stars are less bright.
The pole star is the brightest of the stars in the Little Dipper, and is the one at the end of the ‘handle’.
These two constellations rotate around the pole star and are always visible in the northern hemisphere.
The Big Dipper looks a bit like a ladle with a long handle (or a dipper). The two stars furthest from the handle are the pointer stars, which you use to find the Pole Star.
Draw an imaginary line through these two stars going upwards out of the cup. The pole star will be along this line, five times further from the top star than the distance between the 2 pointer stars.
Some people like to use cassiopeia to help locate the pole star.
This constellation lools a bit like a 'W' with one side slightly flattened.
Cassiopeia and The Big Dipper rotate on opposite sides round the pole star.
The following graphic shows all three constellations, with a line drawn down to North on the horizon.
On a clear night, away from any built up areas, you will find you can see the little dipper and wont need to use anything else.
With clouds around you should be able to locate Polaris using a combination of the three.
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