A star chart is a map of the night sky. Astronomers divide these into grids to easily use them. They are used to identify and locate astronomical objects such as stars, constellations and galaxies.

They have been used for human navigation since time immemorial. Note that a star chart differs from an astronomical catalog, which is a listing or tabulation of astronomical objects for a particular purpose. A planisphere is a type of star chart.

The oldest star chart known may be a carved ivory Mammoth tusk that was discovered in Germany in 1979. This artifact is 32,500 years old and has a carving that resembles the constellation Orion. A drawing on the wall of the Lascaux caves in France has a graphical representation of the Pleiades open cluster of stars.

This is dated to 33,000 to 10,000 years ago. Researcher Michael A. Rappenglueck has suggested that a panel in the same caves depicting a charging bison, a man with a bird's head and the head of a bird on top of a piece of wood, together may depict the summer triangle, which at the time was a circumpolar formation.

Another star chart panel, created more than 21,000 years ago, was found in the La Tête du Lion grotto. The bovine in this panel may represent the constellation Taurus, with a pattern representing the Pleiades located just above it. The Farnese Atlas is a Roman statue depicting the Titan Atlas holding the celestial sphere on his shoulder.

It is the oldest surviving depiction of the ancient Greek constellations, and includes grid circles that provide coordinate positions. Because of precession, the positions of the constellations slowly change over time. By comparing the positions of the 41 constellations against the grid circles, an accurate determination can be made of the epoch when the original observations were performed.

Based upon this information, the constellations were catalogued at 125 ± 55 BC. This evidence indicates that the star catalogue of the Greek astronomer Hipparchus was used. An early example of a graphical representation of the night sky is the Egyptian Dendera zodiac, dated from 50 BC.

This is a bas relief sculpting on a ceiling at the Dendera Temple complex. It is a planisphere depicting the zodiac in graphical representations. However, individual stars are not plotted.

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