Mapping The Night Sky Using Ursa Major

Mapping The Night Sky Using Ursa Major

Ursa Major (“Big Bear”) is the third largest constellation, and being so recognizable makes it a natural reference point for locating several important constellations of the night sky.

Ursa Major: The 7 brightest stars in this constellation form a distinctive shape, known separately as the Plough or Big Dipper, although the entire constellation is spread over a greater area of the sky. It is the most famous of all Northern constellations and is circumpolar in England and the Northern United States.

Ursa Minor: The 7 main stars of this constellation form a shape similar to Ursa Major, but with the tail of the bear pointing in the opposite direction. Ursa Minor (“Little Bear”) has been more universally observed than any other constellation on account of the close proximity to the north celestial pole of its brightest star Polaris (North Star). A line through Ursa Major’s last two stars, Merak and Dubhe, also known as ‘the pointers’, leads to Polaris, with the bright star having been used to tell direction and time for thousands of years.

Cassiopeia: A line through the last star at the handle end of the Big Dipper and through Polaris will lead onto a conspicuous W shaped group of stars called Cassiopeia. This constellation depicts a mythological Greek queen by the same name who was punished for her boastfulness by being condemned to eternally circle the sky on her throne, which sometimes hangs upside down as the constellation revolves in the night sky. The Milky Way runs through Cassiopeia, making it particulary rich in deep-sky objects, including star clusters and galaxies.

Ursa Major MapBootes: An imaginary line that follows the arc of the Big Dipper’s handle leads onto Bootes, which is ancient Greek for ‘plowman’ of  ‘herdsman’. The constellation contains the beautiful orange-red giant star Arcturus (“Bear Watcher”), whose visual magnitude of −0.04 makes it the 3rd brightest star in the night sky, after Sirius and Canopus, but the brightest in the northern celestial heavens.

Virgo: Extending the imaginary curved line further south from Bootes leads to the blue-white star called Spica. This is 15th brightest star, and lies in the constellation Virgo, which is the night sky’s second largest constellation, after Hydra.

Leo: This constellation can be found by following the pointer stars Merak and Dubhe in the opposite direction to Polaris. Leo lies south of Ursa Major, and is so beautiful and striking in its resemblace to the animal it depicts as to make it unmistakable. Its brightest stellar object, Regulus, is a blue-white star from which longitude is reckoned.

Gemini: An imaginary line drawn diagonally through the stars Megrez and Merak in the ‘bowl’ of the Big Dipper, in the oposite direction of the ‘handle’, leads to the constellation of Gemini. The constellation is characterized by two nearly parallel rows of stars; the northern row, headed by Castor, if extended would reach Taurus, while the southern row, headed by Pollux, would reach Orion.

Auriga: A line running through the two top stars in the ‘bowl’ of Ursa Major in the opposite direction of the handle leads to Auriga. This constellation means “the charioteer” in Latin, and contains the night sky’s 6th brightest star, Capella, which is a rich yellow color.

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