Jimmy Westlake: Orion returns
December 1, 2014
Steamboat Springs — "You know, Orion always comes up sideways,
Throwing a leg up over our fence of mountains,
And, rising on his hands, he looks in on me …"
This excerpt from Robert Frost's poem "The Star Splitter" captures in words one of my favorite celestial events — the rising of the magnificent constellation of Orion the Hunter. You can catch him "throwing his leg up over our fence of mountains" in the eastern sky around 8 p.m. in early December.
Orion is one of the first constellations that new stargazers learn to recognize in the sky, even if they don't know it as Orion. When I was a knee-high astronomer, I thought that the prominent stars of Orion's belt and sword formed the Big Dipper.
Nowadays, I find that many other folks make that same mistake. The real Big Dipper is found low in the northern sky this time of year and is not conspicuous when Orion first appears.
Orion is one of only two constellations visible from Colorado that contains two first magnitude stars. Ruddy Betelgeuse (pronounced Beetle-juice) is the star marking Orion's shoulder and icy-blue Rigel (pronounced Rye-jell) marks his foot.
Both stars pop up over the mountains at about the same time, followed immediately by the three stars of Orion's Belt — Alnitak, Alnilam and Mintaka. The three belt-stars rise in a vertical column, halfway between Betelgeuse and Rigel, almost like one of Orion's arrows shot straight up from below the horizon.
Hanging from Orion's Belt is his sword, composed of a fainter trio of stars. The middle star in the sword looks fuzzy, even to the naked eye. This is the Great Orion Nebula, also known by its Messier catalog number, M42.
Aim your binoculars or telescope at Orion's sword for a closer view of one of the largest hydrogen gas clouds in the Milky Way. Dozens of new solar systems are forming in this stellar nursery, nearly 1,500 light-years from Earth.
Greek mythology tells us that the great hunter Orion once boasted that he could kill every living creature on Earth, if he wanted to. The animals of the forest got together and decided they must make a pre-emptive strike just in case Orion was serious. They chose one of their smallest members, the scorpion, to teach Orion a deadly lesson.
Stalking the hunter one day in the woods, the scorpion stung Orion on the heel. The great hunter wheeled around in pain and collapsed from the scorpion's fatal poison.
The scorpion and the hunter were both immortalized in the stars as our constellations of Scorpius and Orion, but they were placed on opposite sides of the sky so that the two mortal enemies could never be seen together. Orion rides high in the midwinter sky and Scorpius appears low in our midsummer sky.
When you see Orion rising in the early evening, you can be certain that the winter snows are not far behind. Welcome back, old friend.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out Westlake's new "2015 Cosmic Calendar" of sky events on his website at http://www.jwestlake.com. It features 12 of his best astrophotographs and a day-by day listing of cool celestial events that you and your family can enjoy watching in 2015. Proceeds from the sale of Cosmic Calendars help to support the CMC SKY Club.