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Zeta Orionis (Alnitak: The Girdle) is a blue-white
supergiant (as are so many stars in Orion).
The three stars that make up the Belt are moving at different proper motions, so in several hundred thousand years the belt will have disintegrated. But then, the rest of this and the other constellations will have changed as well, as the stars continue to move individually through space in their own particular direction. Alnitak is a multiple binary with a fourth-magnitude companion (difficult in binoculars) as well as a very faint 10th magnitude companion. Like epsilon, zeta is surrounded by a gaseous nebula, difficult to see in binoculars. Indeed, the famous 'Horsehead Nebula' is found just south of the star, but not even telescopes bring out its texture. Long-exposure photography is needed to see the darker regions which give the nebula its name. The entire belt easily fits in one binocular view: binoculars. Just southwest of zeta is sigma (which you can also visit) and below this, right at the bottom left, is the complex known as the Great Orion Nebula, one of the most fascinating objects in the heavens: binoculars. Telescopes are useful, but a good pair of binoculars may be useful as well, particularly if you enjoy a clean dark sky. Otherwise the nebula might be difficult to distinguish, and the stars it contains just may look a little 'fuzzy'. |