The Constellation Directory

Abbreviation: UMa
Genitive: Ursae Majoris
Constellation family: Ursa Major
Nearest constellations: Boötes, Camelopardalis, Canes Venatici, Coma Berenices, Draco, Leo, Leo Minor, and Lynx
Right ascension: 10.67h
Declination: 55.38°
Visible between latitudes: +90° and -30°
Square degrees: 1280
Luminary: Alioth (Epsilon Ursae Majoris)
Named stars: Alioth, Dubhe, Merak, Phad, Megrez, Mizar, Alcor, Alkaid, Tania Borealis, Tania Australis, Alula Borealis, Alula Australis
Notable deep sky objects: M40, M81, M82, M97, M101 (Pinwheel Galaxy), M108, M109

About

Ursa Major is the third-largest constellation in the sky and one of the most recognizable. It is visible throughout the year in the Northern Hemisphere. The tail and body of Ursa Major form the well-known asterism called the Big Dipper or the Plough.

The Big Dipper is perhaps most notable for its use during the American Civil War: slaves escaping to the northern USA and Canada would use the Big Dipper (or the "drinking gourd") as a means of navigation at night, since Ursa Major is circumpolar and never completely sets below the horizon. It could therefore be used as a guide from sundown to sunrise.

Mythology

In Greek mythology, Ursa Major represents the nymph Callisto who was a follower of Artemis (also called Diana). Zeus fell in love with Callisto, and she eventually became pregnant with his son. Callisto was transformed into a bear by Hera, Zeus's wife, when their affair was discovered. Zeus placed Callisto in the sky as the Great Bear along with her son, Arcas (represented by the Little Bear).