Pegasus
(PEG-uh-suss)
The
Winged Horse
Pegasus is a
member of the Andromeda group of
constellations that dominate the autumn
and early winter skies.
Visibility at 8
PM (9 Daylight Saving): Andromeda is visible from September
through February, reaching the zenith in December.
What to look for: Pegasus's
body is formed by four stars that make up the Great Square of Pegasus: Scheat (Beta Pegasi), Markab (Alpha Peg.),
Algenib (Gamma Peg), and Alpheratz (Alpha Andromedae), a star he once shared
with Andromeda before the International Union of Astronomers decided not to
make it a time-share.
We see only the front half of the horse, and he is inverted
in our sky. His forelegs extend from
Scheat to Pi and Iota Peg. His neck
extends from Markab to the head at Beham (Theta Peg.) and Enif (Epsilon Peg.).
Pegasus, the Flying Horse
with Andromeda, the
Chained Princess
Pegasus is a flying horse, and we seem to have caught him
upside down, perhaps in the middle of a loop-the-loop.
Andromeda's
mother, Queen Cassiopeia, lies to
the north, with her father, King Cepheus,
beyond that. South of her is Pisces,
the fishes, and beyond that is the Sea Monster Cetus, ready to devour her. And to the east is the Greek Hero, Perseus, fresh from his recent exploit
of ridding the world of the Gorgan Medusa, as told on his own page.
Constellations of Andromeda's Story
Mythology: Pegasus was a favorite creature in Greek
mythology, and plays a roll in many myths.
He first appears in the story of Perseus and Andromeda. When Perseus slew the Gorgan Medusa, a few
drops of her blood fell into the sea, and Pegasus emerged, the offspring of
Medusa and Poseidon (Neptune in Latin), God of the Sea. In some versions of the story, Perseus rides
the friendly Pegasus to Ethiopia just in time to save Andromeda from the sea
monster Cetus.
In other versions, Pegasus only does a walk-on, and Perseus
continues his travels using the winged sandals of Hermes (Mercury), the
Messenger of the Gods. In either case,
Pegasus has many other adventures.
For a time, he served Zeus (Jupiter), King of the Olympian
Gods, as a bearer of that god's trademark weapon, the thunderbolt. The flying horse encounters other
mythological characters, most notably the hero Bellerophon. Together, they fought the Chimaera, a fire
breathing monster with the head of a lion at one end, and that of a snake at
the other. While Pegasus deftly
maneuvered out of harm's way, Bellerophon stuffed the monster's mouths with
lead which melted in the flames and suffocated the creature.
In more recent years, Pegasus has been a trademark for an
oil company, and has signed on with Disney to co-star with the animated version
of Hercules.
A deeper look: Draw an imaginary line from the North
Star, Polaris (Alpha UMi.) through Alpheratz (Alpha And,) and Algenib (Gamma
Peg.) along the eastern side of the Great Square of Pegasus. Continue that line
to the Celestial Equator, and you come to a point not far from the Vernal
Equinox, the starting point of the grid astronomers use to measure the
positions of things in the heavens.
Meridians are lines from one Pole to the other perpendicular
to the Equator. Four of those
Meridians, the ones that run through the Equinoxes and the Solstices, have a
special name. They are called Colures. Together with the Equator and the Ecliptic,
they form a skeleton of the co-ordinate system of the heavens. They are the main rings of an armillary
sphere, a sort of stripped down celestial globe sometimes used as a sundial.
Armillary Sphere
The Vernal Equinoctial Colure, as we have seen passes
through the Great Square of Pegasus,
the Flying Horse. 90° to the west, the
Winter Solstitial Colure runs through Sagittarius,
the Centaur Archer -- half horse and
half human. 90° west of that, the
Autumnal Equinoctial Colure runs through
Centaurus, the other Centaur.
Another 90° farther yet brings us to the Summer Solstitial Colure, which
just happens to run through yet another oddball horse, Monoceros, the Unicorn.
Each of these constellations is therefore a Horse of a
Different Colure.
