Steady as the Pole Star

He who exercises government by means of his virtue
may be compared to the north polar star,
which keeps its place and all the stars turn towards it.
-Confucius, philosopher and teacher (c. 551-478 BCE)
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The word "North Pole star" is merely the designation for the star whose apparent position
is close to the north-celestial pole; this position is currently occupied by the star Polaris.

But even Polaris considered to be 'steady', 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 again 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.

The very long time interval (25700) is the reason we tend to ascribe the changeless, fixed state to the pole star.

The pole star is known in sanskrit as dhruva nakshatra . The dictionary meaning of the word is: "fixed, firm, immovable, unchangeable, constant, lasting, permanent, eternal". The puranic story of Prince Dhruva is available at http://en.wikipedia.org/wiki/Dhruva

Like a wobbling top, the orientation of the Earth's north-south axis is slowly but continuously changing, tracing out a conical shape in a cycle of approximately 25,765 years. This movement, known as precession, is caused by the gravitational forces of the Sun and the Moon, and to a lesser extent other bodies, on the equatorial bulge of the spinning Earth.

Ayanamsa
The difference between the starting point of the Tropical and Sidereal Zodiacs, due to the precession of the equinoxes. There are several in use in India today, but the official government-sanctioned Lahiri ayanamsa (22°27'37.7") is the most widely used. The other popular ayanamsas are Krishnamurti (22°21'50") and Raman (21°00'52") though it should be mentioned that there are at least 3 different versions of Lahiri, plus other lesser used models.

More at:
http://en.wikipedia.org/wiki/Celestial_pole
http://en.wikipedia.org/wiki/Precession_of_the_equinoxes
http://en.wikipedia.org/wiki/Equatorial_bulge
http://www.yeatsvision.com/GreatYear.html