The International Astronomical Union (IAU) divides the sky into 88 official constellations with precise boundaries, so that every direction belongs to exactly one constellation. These are mostly based upon the constellations of the ancient Greek tradition, passed down through the Middle Ages.

The zodiac includes the following 12:

In addition to these 12, Ptolemy listed also the following 36 (which now count as 38, due to the break-up of Argo Navis):

In more recent times this list has been added to, first to fill gaps between Ptolemy's patterns (the Greeks considered the sky as including both constellations and dim spaces between) and second to fill up the southern sky as European explorers journeyed where they could see it. The 38 new constellations are:

Other proposed constellations didn't make the cut, most notably Quadrans Muralis (now part of Boötes) for which the quadrantid meteors are named. Various other less official patterns have existed alongside the constellations called asterisms, and include:

One ancient asterism, Coma Berenices, is now officially a constellation.

See also: list of constellations by area