An old chart depicting Taurus the Bull
©2000 www.ArtToday.com
The constellations we recognise today have
seen many changes over the millennia of human history. Some have
their origins well and truly lost in the mists of time and some are recent
in our history. This month we will take a look at how they came to
be known as they are today.
Which constellation is the oldest? No one
really knows but some are very old indeed. Ursa Major is thought
to be one of the oldest of all, with it's roots reaching back to when the
Ice Ages gripped the earth. The constellation is known to the
native peoples of both Siberia and Alaska, suggesting that the Great Bear
was recognised before the ice melted and broke the land bridge between
the two continents, creating the Baring Straight.
The ancient Egyptians had their own constellations
that may have dated back to end of the last Ice Age as well.
Their name for the bright star Vega was "The Vulture Star", referring to
when it was last the northern pole star 14,000 years ago.
The ancient Babylonians (circa 5600 B.C.)
created some constellations but they also used some that had been
made before. As they kept accurate and detailed records of
celestial events they were one of the first peoples to realise how to predict
solar eclipses, to trace the path of the sun through the stars (what we
call the ecliptic) and they may have created the first of what we call
the Zodiac; We know these as Sagittarius, Pisces, Gemini and Virgo.
While a lot of the constellations we now
use are associated with Greek mythology, the ancient Greeks did not invent
the shape of the constellations, but added their own stories to the constellations
that already existed. Aratos, in 270 B.C. listed 42 constellations
that he knew and were already established. Ptolemy listed 48 constellations
in the 2nd Century A.D. which he was summarising from previous works,
including the first man to accurately chart the stars, Hipparchus
(circa 150 B.C.).
The Chinese independently developed their
own detailed constellations but they were not recognised by the Western
world. They recorded their observations very accurately though and
those records can still be used today to pin-point the location of past
supernovas, comets and other celestial events.
A woodcut print of the northern sky, 16th century
From The Complete Woodcuts of Albrecht Durer, 1515
© 2000 www.ArtToday.com
The constellations of the southern sky
were not added until the Europeans began sailing far across the globe and
the sailors found an unfamiliar sky. Johann Bayer (1572-1625) was
the next person to considerably add to the number of constellations.
He added 12 in all, including Musca the fly, Dorado the Golden Fish,
Pisces Volans the Flying Fish and Chameleon. Johannes Hevelius (1611-1687)
added a few more, including Leo Minor the Lesser Lion and Lynx. The
last group of new constellations was created by Nicholas Louis de Lacaille
(1713-1763) and two Dutch navigators Peitr Dirksz Keyser and Frederick
de Houtman. Lacaille named most of his constellations after new and
important scientific apparatus of his time. From him we gained a
number of small faint constellations such as Fornax the Furnace, Antlia
the Air Pump, Horologium the Pendulum Clock and Microscopium the Microscope.
The constellations did not have fixed boundaries
either, The ancient Greeks only considered those stars that formed
the pattern of the constellation to be part of it. The first printed
charts which appeared in the 16th century had no boundaries marked as they
were meant as a guide to the naked-eye stars. Eventually uranographers
(those who charted the stars) began roughly drawing in boundaries as it
suited them and no two matched exactly.
By the end of the 19th century it was all
starting to get a bit messy and it would be easier if everyone used the
same constellations that had the same boundaries. So in the 1920's
the newly formed International Astronomical Union charged frenchman Eugene
Delaporte with the task of creating a uniform sky for astronomers to use.
The 88 constellations we now use were presented by Delaporte in 1930.
This is why the astrologer's Zodiac does not match the modern sky.
Astrologers assign exactly 30 degrees of the ecliptic to each representative
constellation/sign. To an astronomer the Zodiac has no meaning other
than an interesting piece of history that helped ancient civilisations
keep track of the seasons, as the sun clearly travels through more than
12 "modern" constellations on it's yearly journey.
The southern sky, as it was then known.
From The Complete Woodcuts of Albrecht Durer, 1515
© 2000 www.ArtToday.com
Some constellations that didn't survive
or fell out of favour include Felis the Cat, Le Renne the Reindeer, Globus
Aerostaticus the hot-air balloon (a tribute to the Montogolfier Brothers),
Cerberus the Three-headed Dog, Robur Carolinum the Oak of Charles (this
one was added by Edmund Halley in an effort to curry the Royal favour)
and Triangulum minus. Vulpecula and Anser, the Fox and Goose, was
shortened to Vulpecula. Antinous, a constellation mentioned by Ptolemy,
was incorporated into Aquila the Eagle. Cor Caroli, the Heart of
Charles, was a one star constellation created by the physician to King
Charles II to honour Charles I. It is now recognised as the brightest
star in Canes Venatici the Hunting Dogs. Malus the Mast was created
by Lacaille when he split up Argo Navis but it has now become part of Pyxis
the Compass. Scorpius once had long claws that are now part of Libra
but we are reminded of this by the proper names of the stars, Zubenelgenubi
the Southern Claw and Zubeneschamali the Northern Claw. The Pleiades
were once considered a constellation on their own but now reside inside
the boundaries of Taurus.
This article is ©2000
Stargazers Astronomy
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