Star chart

A star chart is a special kind of map that shows the night sky with many astronomical objects like stars, constellations, nebulae, galaxies, and planets placed on a grid. These maps help people find their way around the stars and learn more about the objects in space.

People have used star charts for a very long time to help with navigation on Earth and at sea. They are different from an astronomical catalog, which is more like a list of space objects for a specific job. Some tools that use star charts are the astrolabe and planisphere, which help stargazers explore the night sky.

History

Prehistory

Ancient people may have made star charts. The oldest known example might be a carved ivory Mammoth tusk found in Germany in 1979. It is 32,500 years old and has a carving that looks like the constellation Orion, but this is not certain.

A German researcher suggested that drawings on the wall of the Lascaux caves in France could show the Pleiades stars. These drawings are very old, from 33,000 to 10,000 years ago. He also thought a panel in the same caves might show the Summer Triangle. Another drawing of the Northern Crown constellation was found in a cave in Spain, made around the same time.

Antiquity

The oldest known accurate star chart comes from ancient Egyptian astronomy in 1534 BC. The earliest star lists were made by Babylonian astronomers in Mesopotamia during the late 2nd millennium BC. The oldest Chinese star lists date to the Warring States period (476–221 BC), but the earliest surviving Chinese star chart is from the 5th-century BC Tomb of Marquis Yi of Zeng. It shows Chinese constellations by name but not individual stars.

Medieval

The oldest surviving manuscript star chart is the Dunhuang Star Chart, found in the Mogao Caves of Dunhuang in Western China. It is dated to between 705 and 710 AD and shows 1,345 stars grouped into 257 patterns.

During the Song dynasty, Chinese astronomer Su Song wrote a book with five maps of 1,464 stars, dated to 1092. In 1193, astronomer Huang Shang made a planisphere that was engraved in stone in 1247 and still exists in Suzhou.

Early modern

During the Age of Discovery, new constellations were added from records of Dutch sailors Pieter Dirkszoon Keyser and Frederick de Houtman. Their work led to the 1601 globe of Jodocus Hondius, which added 12 new southern constellations. Johann Bayer’s Uranometria in 1603 was the first atlas to chart both hemispheres and introduced a way to name the brightest stars using Greek letters.

Polish astronomer Johannes Hevelius published a star atlas in 1690 with 56 large maps and introduced 11 more constellations.

Modern

In 1824, Sidney Hall made star charts called Urania's Mirror. These were based on Alexander Jamieson’s A Celestial Atlas and had holes so they could be held up to a light to see the stars.