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'''Constellations''' are the random arrangement of the stars visible to the naked eye that has remained essentially unchanged since the time of the first written records. One of the earliest complete lists we have was compiled in about 120 BC by the [[Greek]] astronomer [[Hipparchus]], and all the stars that he described can be found, with the same brightness and in practically the same place, in our skies today.

'''Constellations''' are the random arrangement of the stars visible to the naked eye that has remained essentially unchanged since the time of the first written records. One of the earliest complete lists we have was compiled in about 120 [[B.C.]] by the [[Greek]] astronomer [[Hipparchus]], and all the stars that he described can be found, with the same brightness and in practically the same place, in our skies today.

Traditionally, constellations represented mythical or semi-mythical beings.  Over half the constellations were recognized and mentioned by [[Hipparchus]] (and by [[Ptolemy]], whose star catalogue came down to us through the [[Muslim]] scholars as the "[[Almagest]]"). The remaining constellations, mostly in the [[Southern Hemisphere]] were not named until the sixteenth and seventeenth centuries.

Traditionally, constellations represented mythical or semi-mythical beings.  Over half the constellations were recognized and mentioned by [[Hipparchus]] (and by [[Ptolemy]], whose star catalogue came down to us through the [[Muslim]] scholars as the "[[Almagest]]"). The remaining constellations, mostly in the [[Southern Hemisphere]] were not named until the sixteenth and seventeenth centuries.

Few of the groups of stars that form constellations look much like the objects they represent. Much imagination is needed to see the "pictures" seen by those gazing at the skies so many years ago.

Few of the groups of stars that form constellations look much like the objects they represent. Much imagination is needed to see the "pictures" seen by those gazing at the skies so many years ago.

As the earth moves around the [[sun]] in its yearly cycle, the sun appears to "move" through the constellations. The path is known as the ecliptic.  

As the earth moves around the [[sun]] in its yearly cycle, the sun appears to "move" through the constellations. The path is known as the [[ecliptic]]. The [[Babylon]]ians who used the [[duodecimal system]] of twelve, divided the ecliptic into twelve zones, each of them occupied by a constellation, the twelve constellations of the twelve signs of the '''zodiac''', used in [[astrology]]. According to [[Josephus]] these twelve signs were part of the embroidery of the Veil in [[Temple of Jerusalem|Herod's Temple in Jerusalem]].<ref>''Wars'' 5.5.4 [214]</ref>

In antiquity the beginning of the year was reckoned from the start of spring, called the vernal [[equinox]]. The vernal equinox and the autumnal equinox are the two days each year when day and night are equal in length. The constellation through which the sun is passing at the time of vernal equinox changes slowly with the centuries, and therefore the stars associated with the season of spring also change slowly.

In antiquity the beginning of the year was reckoned from the start of spring, called the vernal [[equinox]]. The vernal equinox and the autumnal equinox are the two days each year when day and night are equal in length. The constellation through which the sun is passing at the time of vernal equinox changes slowly with the centuries, and therefore the stars associated with the season of spring also change slowly.