Locate Cassiopeia the Queen

Erick wrote:

Do you have any information on Cassiopeia’s Chair?

Erick, you’ve used the lovely old-fashioned name for this constellation. In the 1930s, the International Astronomical Union (IAU) gave this constellation the official name of Cassiopeia the Queen. But sky watchers still see the chair, and speak of it.

The official borders of the constellation Cassiopeia (and all 88 constellations) were drawn up by the International Astronomers Union in the 1930's. Read more

In the 1930s, the IAU – an organization of professional astronomers – decided to define boundaries and “officially” name 88 constellations. This is the realm of night sky they identified as Cassiopeia. Read more.

Cassiopeia was an Ethiopian queen in ancient Greek mythology. According to legend, she boasted she was more beautiful than the sea nymphs, called the Nereids. Vanity, in mythology, is never wise.

Her boast angered Poseidon, god of the sea, who sent a sea monster (Cetus the Whale) to ravage the kingdom. To pacify the monster, Cassiopeia’s daughter, Princess Andromeda, was left tied to a rock by the sea. Cetus was about to devour her when Perseus the Hero happened by on Pegasus, the Flying Horse.

Perseus rescued the princess, and all lived happily . . . and the gods were pleased, so all of these characters were elevated to the heavens as stars.

For much of the Northern Hemisphere, Cassiopeia is out all night long every day of the year. At present, Cassiopeia appears in the Northwest at nightfall, and rather low in the north-northeast before dawn, as depicted above. Image credit: AlltheSky.com

For much of the Northern Hemisphere, Cassiopeia is circumpolar, that is, out all night throughout the year. In February, Cassiopeia appears in the Northwest at nightfall and low in the North-Northeast before dawn, as depicted above. Image via AlltheSky.com

But – because of her vanity – Cassiopeia suffered an indignity. At nightfall, this constellation has more the shape of the letter M, and you might imagine the Queen reclining on her starry throne. At other times of year or night – as in the wee hours between midnight and dawn in February and March – Cassiopeia’s Chair dips below the celestial pole. And then this constellation appears to us on Earth more like the letter W.

It’s then that the Lady of the Chair, as she is sometimes called, is said to hang on for dear life. If Cassiopeia the Queen lets go, she will drop from the sky into the ocean below, where the Nereids must still be waiting.

Cassiopeia as depicted by Johannes Hevelius in the 1600s.

Bottom line: This post tells you how to find the constellation Cassiopeia the Queen on winter evenings, and it explains the mythology of this constellation.

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Deborah Byrd