Now is one of the best times of the year to enjoy the majesty of Orion the Hunter at a convenient hour.
Orion will be directly south around 9 p.m. and 50 to 60 degrees above the Southern horizon. Orion and the Big Dipper (part of Ursa Major the Great Bear) are the two most famous constellations in the sky. They deserve this acclaim, because they are large and composed of bright stars. Orion has especially bright, colorful stars, and actually looks like what it is supposed to represent. Take out a star chart or use a cellphone application to identify the brightest stars in the Hunter.
Remembering stars’ names is challenging, but the brightest stars in Orion are easy to see. They have interesting names and contrasts in color, and represent enormous supergiant stars far larger and brighter than the sun. Large stars are like mythical heroes — they blaze brightly and die young. Their supercharged lives last only a few million years. The sun, a more modest-sized star, is already nearly 5 billion years old and will live billions of years more.
Most stars look white at first glance. Star colors are subtle, but with practice, you can distinguish different hues. Red stars have low temperatures compared with the sun, while blue stars are very hot. Betelgeuse is a red star, while Rigel is a blue one. The stars in Orion’s “belt” — Alnitak, Alnilam, and Mintaka — are supergiant blue stars. Saiph is so hot, much of its output is ultraviolet, light which is not visible to the human eye. Bellatrix is unique because it is not associated with the other stars in Orion. It is much closer to us, and is a foreground star superimposed on the other stars in Orion. However, it is keeping good company.