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Sky Chart and Artist Rendering of Ursa Major
Origin:
This star group has been associated with a bear for not less than 3000
years, even between isolated continents. At various times throughout
history, the famous "Big Dipper" asterism has been known as a
ladle, plow, wagon, coffin, bear, reindeer, and - in ancient England -
King Arthur's Chariot (a name which did not endure). Ursa
Major ranks as the third largest constellation in the sky.
Information:
Probably the most recognized star patterns in the northern sky, the
"Big Dipper" of Ursa Major culminates high in the sky at 9 pm on
May 6. The seven stars of the Dipper (and 10 others nearby) are not
an accidental grouping. The Dipper is the closest star cluster to
Earth, centered at 80 light years away and about 30 light years across.
The end bowl-stars, Merak and Dubhe,
are often called "pointer stars" since they point to Polaris
along an imaginary line connecting them.
Ursa Major is well-known for its
galaxies. There are at least 15 galaxies brighter than magnitude 11
visible in the Great Bear. This comes as no surprise considering the
constellation borders the great Coma-Virgo cluster of galaxies.
There is one good planetary nebula (gas ejected from a dead star) -- the
Owl Nebula (M97, NGC 3587). While not a particularly bright example
of this type of deep sky object, it is good nonetheless.
Mythology:
Because of the romantic tryst between Zeus and Callisto that resulted in
Arcas' birth, Hera (Zeus' wife) changed Callisto into the Great Bear (Ursa
Major) but left her with knowledge and feelings of her past.
One day, while roaming the forests, she happened upon her son Arcas and,
recognizing him, stood up to hug him. Fearing for his life, Arcas
raised his spear and was set to kill her when Zeus, who happened to be
watching the unfolding scene from Mount Olympus, grabbed them both and
placed them in the heavens. In this version of the myth, Zeus
changed Arcas into Ursa Minor. In other
versions of the myth, Arcas is changed into the constellation Boötes. |
