The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form constellations, appears to rotate westward around a polar axis as the Earth rotates.
At all times, the entire Southern Sky is visible from the geographic South Pole; less of the Southern Sky is visible the further north the observer is located. The northern counterpart is the northern celestial hemisphere.
