Ursa Major, better known as the Great Bear, is a northern hemisphere star constellation. The notable features of Ursa Major include the stars of another well-known and easily recognizable constellation, the Big Dipper.
Ursa Major was first identified as a constellation by the ancient Greek and Roman astronomers. Other civilizations have identified the constellation, but the Greek mythological version held that the constellation was a woman whom the god Zeus had had an affair with, and then turned into a bear on the insistence of his jealous wife, the goddess Hera. You can find the constellation with charts from the Students for the Exploration and Development of Space or from the University of Wisconsin. It is always visible in the northern hemisphere, at a declination of 50 degrees. The constellation consists, essentially, of the legs, a head and a long tail section.
This tail section is perhaps the most notable feature of the constellation of Ursa Major. These seven stars are the brightest in the Great Bear, and also from another well-known constellation, the Big Dipper.
The Big Dipper section of Ursa Major is an important starting point for finding other constellations and important stars. Following a straight line outward from the far end of the “scoop” of the Big Dipper, or the stars of the central “body” of Ursa Major, leads to Polaris, also known simply as the North Star, which moves only slightly in the sky and has therefore long been used for navigation purposes. Polaris, in turn, is the end of the “handle” for another ladle-shaped constellation, the Little Dipper. The Little Dipper is also known as Ursa Minor, or the Little Bear, because in Greek mythology it was the son of the woman who was turned into the Great Bear, Ursa Major.
In addition, a long arc outward along the “tail” of Ursa Major, which is also the handle of the Big Dipper, leads to the constellation Bootes, and its brightest star, Arcturus. Following the same arc beyond Bootes leads to Virgo.
The stars in Ursa Major are also notable for several astronomical features not visible to the naked eye. At least one of the stars in the constellation, 47 Ursae Majoris, is 50 light-years away and is known to have several planets. The bright galaxy Messier 81, and the Pinwheel Galaxy, are visible near this constellation using telescopes. So is the Owl Nebula. Several years ago, when NASA astronomers decided to take an unprecedented picture of the distant early universe, which became the Hubble Deep Field image, they chose a region of space near a star in Ursa Major.
