Finding The North Celestial Pole
- See also Pole star, Polar alignment.
The north celestial pole currently is within a degree of the bright star Polaris (named from the Latin stella polaris, meaning "pole star"). This makes Polaris useful for navigation in the northern hemisphere: not only is it always above the north point of the horizon, but its altitude angle is always (nearly) equal to the observer's geographic latitude. Polaris can, of course, only be seen from locations in the northern hemisphere.
Polaris is near the celestial pole for only a small fraction of the 25,700-year precession cycle. It will remain a good approximation for about 1,000 years, by which time the pole will have moved to be closer to Alrai (Gamma Cephei). In about 5,500 years, the pole will have moved near the position of the star Alderamin (Alpha Cephei), and in 12,000 years, Vega (Alpha Lyrae) will become our north star, but it will be about six degrees from the true north celestial pole.
To find Polaris, face north and locate the Big Dipper (Plough) and Little Dipper asterisms. Looking at the "cup" part of the Big Dipper, imagine that the two stars at the outside edge of the cup form a line pointing upward out of the cup. This line points directly at the star at the tip of the Little Dipper's handle. That star is Polaris, the North Star.
Read more about this topic: Celestial Pole
Famous quotes containing the words finding the, finding, north, celestial and/or pole:
“It makes little sense to spend a month teaching decimal fractions to fourth-grade pupils when they can be taught in a week, and better understood and retained, by sixth-grade students. Child-centeredness does not mean lack of rigor or standards; it does mean finding the best match between curricula and children’s developing interests and abilities.”
—David Elkind (20th century)
“To people off alone, as we were, there is something stirring about finding evidences of human labour and care in the soil of an empty country. It comes to you as a sort of message, makes you feel differently about the ground you walk over every day.”
—Willa Cather (1873–1947)
“The Anglo-Saxon hive have extirpated Paganism from the greater part of the North American continent; but with it they have likewise extirpated the greater portion of the Red race. Civilization is gradually sweeping from the earth the lingering vestiges of Paganism, and at the same time the shrinking forms of its unhappy worshippers.”
—Herman Melville (1819–1891)
“Your enjoyment of the world is never right, till every morning you awake in Heaven: see yourself in your Father’s palace; and look upon the skies, the earth, and the air as celestial joys: having such a reverend esteem of all, as if you were among the angels.”
—Thomas Traherne (1636–1674)
“Not because Socrates has said it, but because it is really in my nature, and perhaps a little more than it should be, I look upon all humans as my fellow-citizens, and would embrace a Pole as I would a Frenchman, subordinating this national tie to the common and universal one.”
—Michel de Montaigne (1533–1592)