¡SkyCaramba! Weekly astronomy blog for the week ending October 20, 2012
A king, a queen, and a princess are immortalized in the northern hemisphere’s sky. For a king important enough to be placed among the stars, not much is said of Cepheus. His wife, Cassiopeia, prefers it that way. She wants all the attention that can be foisted upon her and her daughter Andromeda.
Cepheus was the king of Aethiopia, a kingdom of ancient Greek legend on the north coast of Africa. It has nothing to do with the modern country of Ethiopia. Part of the Cepheus story is that he voyaged with Jason and the Argonauts and earned a rightful place on the celestial dome. The queen and princess were placed there after less honorable acts.
Queen Cassiopeia was very vain. She is often depicted holding a mirror and admiring herself in it. Being beautiful was enough to earn contempt from the gods. Bragging about it earned their wrath. She bragged that her daughter Andromeda was more beautiful than the Nereids (sea nymphs). The Nereids complained about Cassiopeia’s arrogance to their father Poseidon. He sent the sea monster Cetus to destroy the queen’s country.
Cepheus looked for a way to save his kingdom from Cetus. He consulted an oracle who advised him to sacrifice Andromeda to the monster. He tied the princess to a rock by the sea and left her there for Cetus to find. However, a triumphant Perseus happened to be traveling by that way after slaying Medusa. Perseus slew Cetus too and later married Andromeda.
For her part, Cassiopeia ended up in the sky chained to her throne. She’s in such a location that she hangs upside down from it part of the time as her constellation circles the north celestial pole. The goddess Athena arranged the stars to commemorate that near end-of-life moment Andromeda had before her rescue. Perseus is nearby and Cetus is in the sky too.
If you are in the northern hemisphere, you will have little trouble finding Cepheus, Cassiopeia, and Andromeda unless you’re above the Arctic Circle and it’s a time of year when the sun is always up. These constellations circle close to the north celestial pole. The closer a star or constellation is to the pole, the longer it’s up. Cepheus is closest, Cassiopeia is almost as close, and Andromeda is noticeably farther.
You’ll probably think the best time to see them this time of year is in the evening. The king is on the meridian at about 9pm local time. The princess and queen will be on the meridian around midnight.
Here are some links to more information about the mythology behind these constellations.