The brightest star in the night sky is Sirius, the dog star. It is appropriate that the brightest star is located in the constellation Canis Major (Top Dog!). Canis Major is hereby adopted as the official mascot constellation of the Top Dog Forum website.
A constellation is a group of stars that someone with a great imagination can see as an outline of a creature or person (usually mythological), shape, or pattern. The first constellations most likely were discovered (invented, imagined, made-up?) by pre-historic people. Just because they couldn’t read or write doesn’t mean they didn’t have great imaginations.
Ptolemy, a Greek astronomer from almost 2,000 years ago, identified 48 Greek constellations. Today, the International Astronomical Union (IAU) lists 88 constellations. The Greeks could not see the southern night sky so they missed a few. The IAU is the international body in charge of naming celestial objects. If you see a commercial about paying to get a star named after yourself or someone else, save you money. Star names, apparently, are not for sale.
It is a mystery to me how the early Greeks and Romans, or maybe the stone age astronomers, were able to look at a few stars and see an animal, a person, or a set of bookends. We can easily do that with clouds, but very few of us today have the imagination to draw pictures using only a handful of stars. But then, maybe they didn’t have much else to do at night. Well, besides that! And stargazing probably helped take their minds off all the bad predators that prowled in the dark looking for an easy meal. How good are you at outrunning a saber-toothed tiger?
What is Canis Major?
Anyway, back to Canis Major. There are several mythical variations of the story. But the one I accept is that Canis Major is one of Orion’s dogs that helps him chase rabbits across the night sky. I’m not sure which stars make up the rabbits but they must be there somewhere. What dog doesn’t like to chase rabbits?
Another constellation, Canis Minor (small dog) is also one of Orion’s hunting dogs. Canis Minor rises about an hour before Canis Major. The brightest star in Canis Minor is Procyon which means “before the dog.”
Just how important a person does one need to be to have a constellation named after them? Well as for Orion, he was a great hunter, maybe the greatest ever, and he could hunt any animal known or unknown to man, gods, or mother nature. Orion could also walk on waves because his father was Poseidon, the god of the seas.
Being the greatest hunter in the universe may not be such a good thing to be. Mother Earth didn’t approve of Orion’s hunting skills, so she sent a scorpion to kill him. After his death and because Orion was such a hero, Zeus placed Orion among the constellations as a fitting memorial. The dastardly scorpion also has a constellation, Scorpius.
What About Asterisms?
I am glad you asked about asterism (astronomy). They are similar to constellations in that they are a group of stars. I think of them as a poor man’s constellation. If you can’t make out the entire constellation, Ursa Major (big bear), you can probably recognize the Big Dipper asterism, which is part of the Ursa Major constellation. Some other familiar asterisms include the square of Pegasus, the Little Dipper (Ursa Minor), and the Southern Cross (Crux).