The North Celestial Pole is the point in the sky about which all the stars seen from the Northern Hemisphere rotate. Why is it called the north celestial pole? The white line is the imaginary line the pole traces out as Earth wobbles on its axis. The axis is indicated by the red lines coming out the top and bottom poles. Earth turns on its axis once a day (shown by the white arrows). You may be thinking “Why do we have a Changing pole star?” Line CD shows the alignment of the Earth’s axis in 13 000 years’ time. Line AB shows the current alignment of the Earth’s axis, with respect to the background stars. This causes the position of the North Celestial Pole to gradually change. Instead, it slowly rotates in a circle, completing one revolution every 25 800 years. Due to the precession of the equinoxes (as well as the stars’ proper motions), the role of North Star has passed (and will pass) from one star to another in the remote past (and in the remote future). The celestial pole will be nearest Polaris in 2100 and will thereafter become more distant.
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