Where did all the constellations come from?
Thursday, April 21, 2011
OK folks, here is one from the mailbag, "Where did all the constellations come from?"
Well, very good question. The constellations, the patterns and shapes of objects in the night sky have a long history. Many ancient cultures have records of star names and constellations.
The human mind has this peculiar ability, it likes to connect the dots. Seeing stars in the sky gave them a wonderful opportunity to connect the stars into shapes and objects.
We all know the Big Dipper, an asterism forming the back end and tail of Ursa Major, the Great Bear. Numerous ancient cultures observed the shape and gave it their own name.
For example in Great Britain it is called the plow, the French see it as a saucepan, and the Pawnee Indians of North America saw it as a stretcher for carrying a sick person.
Further back, the Mayan Indians in Mexico and Central America saw a parrot, the Hindu in India made it into seven wise men and to runaway slaves in the American south the Big Dipper was a tool to find freedom.
It was always in the north and the phrase they used was "Follow the drinking gourd."
The Babylonians and Sumerians recorded their observations as did the Chinese. Those records from the Arabian astronomers were brought to Egypt by Minoans from the island of Crete when their home was destroyed by a volcano
From Egypt to Greece then Rome and to Europe.
The three "Wise Men" who came from the east to find the place where the Jewish Messiah was to be born had knowledge of constellations, particularly Leo and Virgo.
Constellations have a rich history.
Others were not created until people began to sail around the Horn of Africa and the Cape of Good Hope. There they discovered stars in the southern hemisphere that were totally unknown to them.
In 150 AD a man named Ptolemy, a Greek scientist, published a book he called the "Almagest." In it he outlined some 1,022 stars and put names and shapes to 48 constellations.
As scientific knowledge spread into Europe and many more observers became involved they drew up their own star maps using the basic 48 constellations and adding names of their own. Some lasted, many did not.
In 1922 the International Astronomical Union codified the sky into the 88 official constellations we have today and set their boundaries. This to not so much set the patterns as to indicate a location. Every star and celestial object is inside the boundaries of some constellation. So astronomers today see a location in the sky more so than just a name.
SKY WATCH:
Third quarter moon, Sunday, April 17. Speaking of constellations, here are some you can go outside and see right now about an hour after sunset. Starting in the East the Keystone of Hercules is just above the horizon. Just above it is the kite shape of Bootes with bright Arcturus on the right end of the kite. Swinging to the southeast find the lopsided rectangle of Virgo.
Saturn is about in the middle on the right side. Above Virgo to the right is Leo, the Lion. Continue down from Leo through fellow zodiacans Cancer and Gemini to the western horizon. On to the north we find our old friend the Big Dipper, Little Dipper and the "W" of Cassiopeia who is hugging the horizon.
NEXT WEEK:
More astronomical blathering about constellations.