A constellation who needs no introduction

For the week ending January 22, 2011

The best constellation for the beginning astronomer is Orion, the Hunter. It’s the brightest of all 88 modern constellations, and the easiest to recognize. If you recognize just one star group in the night sky, it’s probably Orion’s belt.

Orion is a winter constellation for those of us in the northern hemisphere. In January, Orion is rising just as it gets dark outside. It stays up all night.

The three belt stars (from east to west) are Alnitak, Alnilam, and Mintaka. Look at Alnilam in a telescope and you’ll see an area of light around it. That’s NGC1990, a cloud of star material lit up by the middle star.

A little south of Alnitak is the famous Horsehead Nebula, so named because of what it sort of looks like. It’s actually not easy to see. Photographs of it take long exposure times. You will need a big telescope and very dark skies to see anything that comes close to what the pictures look like.

South of the belt stars are Orion’s dagger. It appears to be made of three stars. However, an investigation through a telescope reveals that the middle one is actually a double star and a nebula. There are numerous other nebulae and double stars in Orion. A careful look through binoculars or a telescope will show many of them to you.

The bright orange star that is one of Orion’s shoulders is Betelgeuse. The other shoulder star is Bellatrix. On the same side as Bellatrix, bright blue Rigel is one of the hunter’s knees (or a foot by some accounts). Rigel is one of the brightest stars when you consider absolute brightness (how bright various stars would be if viewed at the same distance). The other knee or foot is Saiph.

If your sky is dim enough, you’ll make out a few stars that form Orion’s head. You may even be able to see something he’s holding in front of him. Some sky watchers of long ago called it a shield. Others called it an animal skin.

One ancient legend about Orion says a scorpion fatally bit him after he boasted about how great a hunter he was. The gods placed them at opposite locations in the sky to prevent any further trouble between them. And so, Scorpio is a constellation of summer.

Cultures all around the world have had legends about Orion or its belt stars. The constellation was a hunter in many old tales. It has also been a canoe, a rebellious person, and a Mother Earth goddess. The belt stars have been animals being hunted, the footprints of a god who terrifies fleas into hiding during winter, and the three magi who blessed the baby Jesus.

Look at Orion yourself and think about how imaginations of long ago connected the distant dots. You could make another connection by researching the constellation’s importance to your ancestors. If the winter night doesn’t send a chill down your spine, maybe contemplation like that will.