Diurnal Circles

DIURNAL CIRCLES


The daily motions of celestial bodies (diurnal motions) appear as shown below:


Time lapse photograph of the northern hemisphere night sky. The only stationary point is the location of the North Celestial Pole. Each arc is for an individual object. Roughly, for how long was the photograph exposed?



This daily (diurnal) motion is easily understood as the rotation of the Celestial Sphere on an axis which passes through the north and south poles of the Earth.