Ursa Major

Ursa Major is a large northern-sky constellation containing the Big Dipper asterism. Its stars Merak and Dubhe point toward Polaris.

Big Dipper: A prominent asterism of seven stars within Ursa Major, shaped like a dipper or wagon. Its seven-star outline is the constellation’s most recognizable pattern.
Polaris: The current northern pole star, located close to the north celestial pole in Ursa Minor. Extending the line from Merak through Dubhe leads approximately to Polaris.
Ursa Major in Greek mythology: A Greek mythological constellation identified with Callisto, transformed into a bear and placed in the sky. The constellation’s Latin name preserves the Greek tradition of the Great Bear.
Messier izar?: A binary star system in Boötes, often called Pulcherrima for its contrasting colors. It is not in Ursa Major; this tempting neighboring object clarifies the constellation’s boundary.
Merak: A blue-white star in Ursa Major, designated Beta Ursae Majoris. Merak forms one of the two pointer stars in the Big Dipper’s bowl.
Celestial navigation: Navigation that uses the positions of celestial bodies to determine direction or location. The Big Dipper’s pointer stars offer a practical route to north in the night sky.
Callisto: A nymph in Greek mythology who was transformed into a bear and placed among the stars. Her story is one of the best-known explanations for Ursa Major’s name.
Messier 40: A visual pair of stars in Ursa Major, catalogued by Charles Messier as a deep-sky object. It is an unusual catalog entry inside the constellation, though not a true physical pair.
Dubhe: An orange giant star in Ursa Major, designated Alpha Ursae Majoris. Dubhe is the other pointer star, paired with Merak to locate Polaris.
Circumpolar star: A star that never sets below the horizon for an observer at a given latitude. Much of Ursa Major remains visible year-round from many northern locations.

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