All winter long weíve been delighted by the starlight of what I lovingly refer to as ďOrion and his gangĒ. Not only are these the best set of constellations the winter night sky has to offer but some of the best and brightest stellar luminaries in the celestial dome anytime of the year. As evening commences much later now in mid-April, Orionís gang dominates the western skies with Orion the Hunter himself just about at the western horizon and setting in the west during the midnight hour. As spring progresses Orion and his gang start out the evening lower and lower in the west and by around mid-June or so theyíre completely gone from the evening sky. We wonít see them again until next autumn, as the Earth in its orbit around the sun and the night time side of our world faces their direction. I love summer but I hate to see some of my best celestial buddies go away on summer vacation.
Speaking of buddies, one of the members of Orionís gang, the constellation Gemini the Twins, is just above and a little to the left of Orion in the western skies. Gemini lives up to its name in a couple of ways. First of all its brightest stars, Castor and Pollux, are side by side and at least to the naked eye identical in brightness. In fact, nowhere else in the sky will you find two identical stars as close to each other as they are. Secondly, the stars Castor and Pollux mark the heads of the Greek mythological twins of by the same names. Even in light polluted skies, unless youíre really in the middle of a big city, youíll see a crooked line of stars below each of the stars Castor and Pollux that outline the bodies of the twin brothers. Tonight and tomorrow night the first quarter moon will help you to find Gemini very easily. Tonight the moon will be in Geminiís midsection just below Castor and Pollux, and tomorrow night the moon will be just to the left of Geminiís brightest stars.
According to Greek mythology, Castor and Pollux were the twin sons of Leda, the mortal queen of Sparta. However they had two different fathers. How can that be if theyíre twins? Well this is a family column but letís just say they had really wild parties back then. Castorís father was Ledaís husband King Tyndarus, while Pollux was the love child of Leda and Zeus, the king of the Greek Gods. That made Castor a pure mortal, but Pollux was a half god.
That didnít matter to Castor and Pollux. They were inseparable and the best of friends. As they grew into young men together, Castor became an expert horseman and Pollux a championship boxer. But even though they had separate vocations they remained very close.
One of their claims to fame was they were on the ship of the Argonauts in the famed voyage of Jason and the Argonauts, who set sail in pursuit of the fabled Golden Fleece. Jason needed the Fleece to earn the right to be King of Iolcus in the Land of Thessaly. Apparently it was a great job that paid pretty well. Anyway, during the voyage the mighty ship was tossed in a violent and massive nocturnal thunderstorm and was in danger of slipping under the raging sea. In the story Castor and Pollux get all the credit for calming the seas, but it was actually the great Greek musician Orpheus who was the real hero. He got out his harp and played every beautiful melody he knew to appeal to the gods to calm the storm. It must have been beautiful music to the collective ears of the deities because the winds calmed and the skies cleared. Castor and Pollux were standing on the deck as dumbfounded as the rest of the crew by the sudden calming of the seas when two bright stars shown directly over their heads. The crew mobbed the twins in adoration and ever since then a the Twins were the patron saints of sailors, at least back then.
Several years later as the twin brothers were cruising the bars, they met trouble head on. They met a couple of ladies who they thought were available. They bought them drinks and danced the night away. It was a wonderful time for all, until their jealous boyfriends showed up. Needless to say a rumble erupted and in the fight Castor was fatally stabbed with a sword and tragically died a few hours later in the arms of Pollux.
Castor, being a mortal, went to the underworld at death. Pollux was beyond grief stricken. He deeply loved his brother and longed to see him again, but he knew he never would. Pollux had the blood of the gods in him and gods werenít ever allowed in the underworld. Zeus took pity on his son and being that he was the head god on Mount Olympus, he bent the rules and allowed Pollux to enter the underworld each day for at least a little while to see his dead brother. Zeus was so impressed with this brotherly love that he put the constellation Gemini in the skies as an honor to his favorite sons.
Astronomically the star Castor, at 50 light years away, is one of the most interesting stars on the celestial stage. Castor looks like one star to the naked eye, but with modern telescopes astronomers have resolved that Castor is actually a collection of six stars all dancing around each other in a complex orbital pattern. If you lived on a planet in that system, you would have six sunrises and six sunsets every day. Chances are, though, that planets would have a hard time surviving in the gravitational chaos. Thereís better than an even chance that planets would be shot out into interstellar space to live the life of planetary orphans. Pollux is a single giant star, more than 10 times the diameter of our sun, shining a little more than 34 light years, with just one light year equaling almost six trillion miles!
The best small to moderate telescope target in Gemini the Twins is Messier object 35, or M35 for short. Itís a beautiful open cluster of young stars that occupies the area of the full moon in our sky. Itís easy to find, right next to the foot of the twin Castor. It lies over 2500 light years away and its age of 100 million years makes them stellar toddlers believe it or not. M35 is a must see with your scope.
Diagram of GEMINI...Click