Monday, January 31, 2011

Locating North Star

When I was a small child, my father showed me the famous Great Bear. I later came to know that the constellation was astronomically known as the Ursa Major. The constellation is dominated by a seven-star shaped “The Plough” or the Big Dipper. The component stars are the seven brightest of the formal constellation Ursa Major. The Plough can be seen every night easily as it is vividly visible. I did not know the importance of the Plough then, but many years later.

Many years later as part of my basic map reading training in the military academy, I was introduced to many more astronomical shapes that dot the sky. It was then I came to know that in conjunction with the Plough and another constellation Cassiopeia, one can determine the North Pole for direction keeping. The last two stars of the Plough are called pointers and when a line is drawn one can find the North Pole easily. And to be sure, of the exact location of the North Pole, the W-shaped constellation Cassiopeia containing five stars comes handy. Located almost opposite to the Plough on the other side of the North Pole lies this W-shaped constellation. By joining the pointers and the central star of the Cassiopeia, one can easily determine the exact location of the North Pole.

For novices in astronomy, this could be the jumpstart to know the shapes of the basic constellations and how these help us to keep directions in a moonless night even without a compass.


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