A constellation is a grouping of stars that is used to help identify a region of the sky. The individual stars within a constellation generally have no physical relationship, as they are at a varying distances from our observation point on the Earth. Different cultures developed their own groupings of stars, as they each had their own stories to tell in the night sky. For example, the constellation of Ursa Major has variously been identified as:

• An Ox and his handler (by the Egyptians, as recorded in paintings found in the tomb of Seti I);
• The tail of a Great Bear (by the Greeks and Native Americans); and
• A celestial bureaucrat carried on a cloud (by the Chinese).

In 1933, the International Astronomical Union specified a definitive set of 88 constellations, based on the groupings introduced by:

• Ptolemy: 48 constellations described in his great work, The Almagest, in the 2nd century AD. These constellations originally came from a variety of sources including the myths and legends of Mesopotamia, Babylon, Egypt and Greece. Ptolemy’s constellations were primarily in the northern hemisphere, as parts of the southern sky were never visible from Greece. One of the largest of these constellations, Argo Navis, was split into 4 smaller constellations Carina (the Keel), Puppis (the Stern), Vela (the Sails) and Pyxis (the Ship’s Compass) by Lacaille in the 1750s.
• 12 constellations were added around 1600 by Johann Bayer in his star atlas, Uranometria, including Dorado (the Swordfish), Musca (the Fly) and Volans (the Flying Fish). These new constellations were not invented by Bayer, but adapted from other sources;
• Jakob Bartsch added a further 3 in 1624: Camelopardalis (the Giraffe), Columba (the Dove, also attributed to Bayer) and Monoceros (the Unicorn);
• Johannes Hevelius devised 7 new constellations late in the 17th century, including Lacerta (the Lizard), Leo Minor (the Small Lion) and Scutum (the Shield);
• Finally, Nicolas Louis de Lacaille devised 14 southern hemisphern constellations in c.1750, including Fornax (the Furnace), Horologium (the Clock) and Teloscopium (the Telescope).

The modern constellations contain a mixture of mythological characters (e.g. Perseus, Andromeda, Orion), animals (e.g. Taurus, Scorpius, Canis Major), scientific apparatus (e.g. Microscopium, Sextans and Caelum the chisel) and everyday objects (e.g. Crater the cup and Scutum the shield). Twelve of the most well-known constellations are the zodiacal constellations that lie along the ecliptic, the apparent path of the Sun through the sky.

The 88 Constellations recognized by the International Astronomical Union