One of the most prominent constellations in the northern hemisphere’s night sky during the winter is The Hunter, Orion. In lore he was a guide to the seasons for mariners and farmers, signaling the onset of winter storms. The Egyptians called him Osiris, God of the Underworld, with the Milky Way his River Styx. His companion dog, Canis Major follows him in his travels across the sky from east to west as the winter progresses.
There are seven major stars in Orion, three in his belt and two each in his shoulders and feet.
The brightest is Betelgeuse, also known as Alpha Orionis using the Bayer system of classification. It is a pulsating red super giant of 0.5 (var.) magnitude. It is located in Orion’s shoulder, in the north east portion of the constellation. It is about 427 light years from earth and is so large that if it was to replace our sun, its outer surface would extend between Mars and Jupiter.
The other star in Orion’s upper body is Bellatrix, a blue super giant of the second magnitude (1.6). It lies about 240 light years from earth and is one of the hotter naked eye stars. It is the Gamma Orionis star.
The Beta Orionis star is Rigel, a blue-white super giant that lies below Bellatrix. It is a first magnitude star (.2); it is over twice the distance from earth as Betelgeuse, somewhere between 700 and 900 light years, depending on whose research you use. It is also a visual binary star.
Directly below Betelgeuse, and across from Rigel is Saiph, also known as Kappa Orionis. It is a blue-white super giant, mid-second magnitude at 2.05, and is 720 light years away.
And now on to the three stars that make up Orion’s belt.
Below the beautiful Betelgeuse is Alnitak, the brightest O Class star in the sky. A double star with a combined magnitude of 1.8, it lies about 800 light years away, it is a hot blue super giant. Classified as Zeta Orionis by Bayer, it hides from most backyard telescopes the amazing Horsehead Nebula, IC434 just to its south.
Next to Alnitak is Alnilam, Epsilon Orionis. It is a hot B class super giant. A second magnitude (1.7) star, it is 1300 light years from earth.
The final star in Orion’s belt is Mintaka, rated as Delta Orionis. With a magnitude of 2.2, it is over 900 light years away. It is also a double star like Alnitak.
Any visit to Orion would not be complete without mention of the wonderful Orion Nebula, that hazy patch lying below the three starred belt. Also known as M42 and M43, this is a vast cloud of swirling gas containing very young stars of magnitude 4 to 8. The asterism Trapezium lies within this nebula.
Much of the Constellation Orion is visible with both the naked eye and with binoculars, making this a popular viewing spot in the northern hemisphere’s winter sky.