How were the constellations named and who named them?

Constellation refers to a group of stars forming a fixed
pattern visible within a particular region of the night sky.  The word constellation
also refers to the region in which a specific group of stars appears.  Astronomers have
divided the sky into 88 areas, or constellations.

One
popularly known group of constellations consist of the twelve signs of the zodiac. Each
of these sign is named after a constellation.

These
constellation have been identified and named over a period of thousands of year. For
most of these constellations we do know when these were identified and who named
them.

People of various early civilizations observed groups
of stars in the northern two-thirds of the sky, and named these groups of stars after
animals and mythological characters.  For example, the constellation Leo was named after
a lion, Pisces after two fish, and Taurus after a bull.  The constellations Andromeda,
Cassiopeia, Orion, and Perseus are named after characters in Greek
mythology.

Between the fifteenth and eighteenth century,
navigators explored the Southern Hemisphere and observed many other constellations which
were not identified till then.  These constellations were named after scientific
instruments and other things as well as after animals.  For example, the constellation
Telescopium was named after the telescope, and Musca was named after the
fly.