Cetus, the Sea-Monster

Cetus is a large constellation, one of Ptolemy's forty-eight, lying in a watery region of sky near the ecliptic and representing the sea-monster of the Perseus and Andromeda myth, the beast sent by Poseidon to devour the princess, slain by the hero. Though usually called the Whale in modern usage, it was the monster of the story in the classical imagination. It contains Mira, a famous long-period variable star whose name means the wonderful, which brightens and fades over some eleven months. In astronomical tradition the constellation is a pattern of stars rather than a zodiac sign, though it lies close to the signs Pisces and Aries. These are the features of Cetus as the classical and modern traditions describe it, distinct from any astrological reading; it is the monster of the great sky-myth written across this part of the heavens.

The stars of Cetus and the neighbouring sky mattered enough to early modern astronomy that Lacaille later carved two purely scientific instrument-constellations, Fornax the furnace and Sculptor the studio, from the faint southern edge of this same general region in the 1750s, extending the ancient sea-monster's watery neighbourhood with figures drawn from the Enlightenment workshop rather than from myth.