Star Tales – Cetus

When Cassiopeia, wife of King Cepheus of Ethiopia, boasted that she was more beautiful than the sea nymphs called the Nereids she set in motion one of the most celebrated stories in mythology, whose characters are commemorated in the sky. In retribution for the insult to the Nereids, the sea god Poseidon sent a monster to ravage the coast of Cepheus’s territory. That monster is represented by the constellation Cetus.

To rid himself of the monster, Cepheus was instructed by the Oracle of Ammon to offer up his daughter Andromeda as a sacrifice to the monster. Andromeda was chained to the cliffs at Joppa (the modern Tel-Aviv) to await her terrible fate.

Cetus was visualized by the Greeks as a hybrid creature, with enormous gaping jaws and the forefeet of a land animal, attached to a scaly body with huge coils like a sea serpent. Hence Cetus is drawn on star maps as a most unlikely looking creature, more comical than frightening, nothing like a whale although it is sometimes identified as one.

The bizarre-looking sea monster Cetus, illustrated in the Atlas Coelestis of John Flamsteed.

Andromeda trembled as the B-movie monster made towards her, cleaving through the waves like a huge ship. Fortunately, at this moment the hero Perseus happened by and sized up the situation. Swooping down like an eagle onto the monster’s back, Perseus plunged his sword into the creature’s right shoulder. The monster reared up on its coils and twisted around, its cruel jaws snapping at its attacker. Again and again Perseus plunged his sword into the beast – through its ribs, its barnacle-encrusted back and at the root of its tail. Spouting blood, the monster finally collapsed into the sea and lay there like a waterlogged hulk. Its corpse was hauled on shore by the appreciative locals who skinned it and put its bones on display.

Cetus is the fourth-largest constellation, as befits such a monster, but none of its stars is particularly bright. Alpha Ceti is called Menkar from the Arabic meaning ‘nostrils’, a misnomer since this star lies on the beast’s jaw. The most celebrated star in the constellation is Mira, a Latin name meaning ‘the amazing one’, given on account of its variability in brightness. At times it can easily be seen with the naked eye, but for most of the time it is so faint that it cannot be seen without binoculars or a telescope. Mira is a red giant star whose brightness variations are caused by changes in size. The star was first recorded in 1596 by the Dutch astronomer David Fabricius, but the cyclic nature of the changes was not recognized until 1638. The name Mira was given to the star by the Polish astronomer Johannes Hevelius in 1662, when it was the only variable star known.