A Day in the Sky

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The pattern of the satrs is almost the same from night to night – that is, the patterns are the same, but their position in the sky changes. Patterns of stars have been given names, and eight – eight different regions of the sky labelled as the different constellations. The constellation move across the sky during the night, some stars falling below the horizon and some rising above it appearing to rotate. In the Northern hemisphere, everything seems to rotate about the pole star.

It is common to make measurements relative to the 'fixed stars'. These are stars so distant that they appear to be fixed in the sky, apart from their nightly and seasonal motion as the Earth tilts on it's axis, while always rotating about the pole star.

The motion continues during the day, but the light from the stars is trivial compared to the light from the Sun, so is not visible. The Sun however, rises in the East and sets in the west, also rotating about the pole star, rising higher in summer and lowest in winter.