Ursa Major

constellation visible throughout the year in most of the northern hemisphere
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Ursa Major is a constellation that can be seen in the northern hemisphere and part of the southern hemisphere. Its name means Great Bear in Latin. It was named that because many different groups of people around the world have thought that its stars look a lot like a bear with a long tail. It is often used as a symbol for north.

Ursa Major
Ursa Major
GenitiveUrsae Majoris
Pronunciation/ˈɜːrsə ˈmər/,
genitive /ˌɜːrs məˈɒrɪs/
Symbolismthe Great Bear
Right ascension10.67
Area1280 sq. deg. (3rd)
Main stars7, 20
Stars with planets20
Stars brighter than 3.00m7
Stars within 10.00 pc (32.62 ly)8
Brightest starε UMa (Alioth) (1.76m)
Messier objects7
Meteor showersAlpha Ursa Majorids
Leo Minor
Coma Berenices
Canes Venatici
Visible at latitudes between +90° and −30°.
Best visible at 21:00 (9 p.m.) during the month of April.
The Big Dipper or Plough.

According to Greek mythology, Ursa Major was once the beautiful maiden Callisto, whom the god Zeus had an affair with. In order to protect her and their son, Arcas, from his jealous wife Hera, Zeus turned Callisto and Arcas into bears. He then picked up the bears by their short, stubby tails and threw them into the sky.[1]

The constellation cannot be seen from the southern areas of Patagonia, South Africa, Australia, and all of New Zealand except the Northland region.

Deep-sky objects change

Several bright galaxies are found in Ursa Major, including the pair Messier 81 (one of the brightest galaxies in the sky) and Messier 82 above the bear's head, and the Pinwheel galaxy (M101), a beautiful spiral galaxy northwest of the star η Ursae Majoris. Other well-known spiral galaxies are NGC 4102, NGC 4605, Messier 108 and Messier 109. The constellation has about 50 galaxies that can be seen with a small telescope. The Owl nebula, the brightest planetary nebula, can be found along the bottom of the bowl of the Big Dipper.

The Big Dipper change

The Big Dipper (or Plough) within Ursa Major

The seven stars in the northeast corner of Ursa Major form an asterism called the Big Dipper (or the Plough in Great Britain). This group has been recognized by almost all groups of people who live or lived in places where it can be seen in the sky and it is one of the best-known star patterns. The Big Dipper is helpful in finding the north star because an imaginary line drawn through the two stars on the right side will point directly at the north star. These two stars are called The Pointers and they are very important on navigation by stars.

All of the stars in the Big Dipper except Dubhe and Alkaid are moving toward the same point in the sky through proper motion. This group of stars is known as the Ursa Major Moving Group.

References change

  1. "Ursa Major in Greek Mythology| the myth of Zeus and Callisto". 20 March 2011.

Other websites change