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Cetus
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Ursa major constellation illustration art. (Big Dipper) stars, space, night sky)
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Latin:
“Whale”
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Cetus

constellation
Written by
Erik Gregersen
Erik Gregersen is a senior editor at Encyclopaedia Britannica, specializing in the physical sciences and technology. Before joining Britannica in 2007, he worked at the University of Chicago Press on the...
Erik Gregersen
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Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
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•History

Cetus, constellation in the southern sky, at about 2 hours right ascension and 10° south in declination. The brightest star, Deneb Kaitos (from the Arabic for “tail of the whale”), has a visual magnitude of 2.04. The most famous star in Cetus is Mira Ceti, or Omicron Ceti, the first known variable star. Mira Ceti changes its brightness from third to ninth magnitude over a period of 330 days. In Greek mythology, Cetus was the sea monster that was sent by Poseidon to devour Andromeda, daughter of King Cepheus of Ethiopia. In some accounts, the Greek hero Perseus used the Medusa’s head to turn Cetus to stone; in others, Perseus killed Cetus with his sword.

Erik Gregersen
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