High Quality Content by WIKIPEDIA articles! The celestial sphere is divided into 89 areas. These are the IAU 88 official constellations of astronomy. Although there are only 88 IAU constellations, the sky is actually divided into 89 irregularly shaped boxes as the constellation Serpens is split into two separate sections, Serpens Caput (the snake's head) to the west and Serpens Cauda (the snake's tail) to the east. From each of these areas of the celestial sphere, incoming X-rays have been detected above the Earth's atmosphere.