The constellations are imaginary figures made of groups of stars forming patterns which allow an observer to easily identify star positions. Most were named in ancient times, after animals or mythological figures. In the 1920’s, the International Astronomical Union fixed the boundaries of the 88 officially recognized constellations. Stars locations are indicated by a Greek letter and their equatorial coordinates.
This map of the Northern Hemisphere sky shows the constellations seen by an observer at the North Pole. The sky seems to turn around an axis (passing nearby the North Star), but it is actually the Earth that is turning relative to the stars.
Click on [play] to rotate.
Rollover the stars to see the names and forms of the constellations.