What Exactly is in the Night Sky? How many constellations are there anyway? There are 88 official constellations recognized today by the International Astronomical Union as determined in 1922. The constellations have definitive boundaries which extend out beyond the star figures. These boundaries were set to include all sky objects, no matter the brightness, to ease the modern study of these sky phenomena. The stars were originally used to navigate oceans and deserts, determine plantings, harvests and the changing of the seasons. Grouping brighter stars into readily recognizable shapes, the constellations, made this study and observation easier. Several constellations that were suggested and added to the sky catalogs have been dropped. These constellations were usually named for kings, typically for political favors and usually didn't last much beyond the timespan of his reign. Obsolete constellations include: Edmond Halley naming of a southern constellation Robur Carolinium (Charles' Oak) for King Charles II of England; as a joke, John Hall invented thirteen constellations named for unappealing animals like a toad, a leech, a spider, an earthworm and a slug.
Where did the modern constellation system come from? From the ancient Sumerians by way of Greece. The oldest description of the constellations as we know them comes from a poem, Phaenomena, written about 270 BC by Aratus. Aratus' work includes those star patterns that are visible from latitude 36° north. This places the location south of Greece and north of Egypt, right where the Babylonians and Sumerians would be watching the skies. Aratus' work also does not include any of the constellations visible near the south celestial pole. An area not visible from this target area. The earth wobbles in its orbit. This is called precession. The areas not accounted for in Aratus' poem, the skies near the south celestial pole, includes the areas that would not have been visible near this target latitude around the year 2000 BC, the time of the Babylonians and Sumerians. For these reasons, the constellations were probably the work of Babylonian and/or Sumerian astronomers. Ptolemy's book, the Almegest, circa 150 AD, included a summary of Greek astronomical information and cataloged 1,022 stars, with estimates of their brightness, and arranged in 48 constellations. Additional constellations have been suggested over the years to fill in the gaps between the existing constellations of Ptolemy's Almegest and the areas of the sky near the South celestial pole. These contributors included the Dutch cartographer Gerardus Mercator in 1551, Pieter Keyser and Frederick de Hautmann who were navigators aboard some of the first expeditions to the East Indies in the early 1600's, the Polish astronomer Johannes Hevelius in 1690 and the French astronomer Nicolas Louis de Lacaille in the 1750's.
In the 5th Century BC: the ecliptic, an imaginary line connecting the constellations through which the sun appears to move, was identified in Babylon and perhaps in Greece. The Babylonians took all the stars of the ecliptic and divided them into the 12 constellations of the zodiac. They developed stories connecting the exploits of the gods with the actions of the sky. The Greeks started to explain the motions of the sky as the actions of gods. As the gods became further removed from the experiences of people, they lost their importance in daily lives. For example, Uranus was the sky and father of Cronus, time. He was killed and chopped into pieces by Cronus who was then defeated by his own son, Zeus. He and his brothers, the Titans, were defeated by Zeus and pushed into Tartarus in the deepest part of Hades. Zeus was seen as representing all atmospheric phenomena (clouds, rain, thunder and lightning) and eventually became the highest civic god with festivals in his honor. His brothers Poseidon and Hades took the seas and the underworld as their respective realms. The gods were given the same weaknesses as man and were ruled by their emotions bringing the gods closer to man then ever before.
There are 61 constellations visible in the northern hemisphere. The list below includes the 48 original constellations named in Ptolemy's Almegest. Names marked with an asterisk were added some time after his work was completed.
Andromeda daughter of King Cephius and Queen Cassiopeia, she is also the wife of Perseus.
Aquarius the water bearer and 11th constellation of the zodiac.
Aquila the eagle.
Ara the alter.
Aries the ram and the first constellation of the zodiac.
Auriga the charioteer.
Boötes the bear driver.
* Camelopardalis the giraffe, a faint constellation proposed by Plancius in the 17th century.
Cancer the crab and the 4th constellation of the zodiac.
Canis Venatici the hunting dogs.
Canis Major the large dog.
Canis Minor the small dog.
Capricornus the sea goat and tenth constellation of the zodiac.
* Carina the keel, part of Ptolemy's original constellation Argo Navis, which was divided by Lacaille in 1763 into Carina, Puppis and Vela.
Cassiopeia the wife of King Cephius and mother of Andromeda.
Centaurus the centaur.
Cepheus the husband of Queen Cassiopeia and father of Andromeda.
Cetus the whale.
* Columba the dove, a faint northern hemisphere constellation introduced by Plancius in the 17th century.
* Coma Berenices or Berenice's hair. It was included as part of Leo by Ptolemy and was listed as a separate constellation in 1551 by Mercator.
Corona Australis the southern crown.
Corona Borealis the northern cross.
Corvus the crow.
Crater the cup.
Cygnus the swan.
Delphinus the dolphin.
Draco the dragon.
Equuleus the little horse.
Eridanus the river.
Gemini the twins.
Hercules the strongman.
Hydra the sea serpent.
* Lacerta the lizard, a constellation proposed in 1690 by Hevelius.
Leo the lion and fifth constellation of the zodiac.
* Leo Minor the small lion, added by Hevelius in 1690.
Lepus the hare.
Libra the scales and seventh constellation of the zodiac.
Lupus the wolf.
* Lynx one of the constellations added by Hevelius in 1690.
Lyra the lyre.
* Monoceros the unicorn, a faint northern constellation introduced by Plancius in the 17th century.
Ophiucus the serpent holder.
Orion the hunter.
Pegasus the winged horse.
Perseus the Hero and husband of Andromeda.
Pisces the fish and 12th constellation of the zodiac.
Piscis Austrinus the southern fish.
* Puppis the stern, part of Ptolemy's Argo Navis.
Sagitta the arrow.
Sagittarius the archer and ninth constellation of the zodiac.
Scorpius the scorpion and either constellation of the zodiac.
* Scutum the shield, a new northern constellation proposed by Hevelius in 1690.
Serpens the serpent.
* Sextans the sextant, one of Hevelius' constellations.
Taurus the bull and second constellation of the zodiac.
Triangulum the triangle.
Ursa Major the great bear.
Ursa Minor the small bear.
* Vela the sails, part of Ptolemy's Argo Navis.
Virgo the virgin and sixth constellation of the zodiac.
* Vulpecula the fox, one of Hevelius' 1690 creations.
Throughout history different cultures have viewed the Heavens in many different ways. These have included such descriptions as:
· a liquid with the stars floating through it like ships on the sea.
· a canopy
· a cupola
· a bell
· an upturned cup
· an umbrella turning around its handle
· a tent
· a tortoise shell
· the solid roof holding the weather (Gauls)
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