Crater is a small, faint southern constellation, one of Ptolemy's forty-eight, representing a cup or goblet, set upon the back of the water snake Hydra. In Greek myth it is the cup of Apollo, tied to the tale of the crow sent to fetch water: the bird dallied and returned late with a water snake as its excuse, and the god set crow, cup, and snake, Corvus, Crater, and Hydra, together in the sky as a lasting rebuke. Its stars are modest and form the shape of a wide-bowled chalice. In astronomical tradition the constellation is a pattern of stars rather than a zodiac sign. These are the features of Crater as the classical and modern traditions describe it, distinct from any astrological reading; it is chiefly of interest for the myth it shares with its neighbours on the serpent's back.
Crater sits beside Sextans, one of Hevelius's 1687 additions carved from the faint, sparsely populated sky along Hydra's back, a instrument-named seventeenth-century figure with no connection at all to the crow-cup-serpent myth that gives Crater itself its meaning. The wide, shallow bowl shape of Crater's outline is often described as one of the more literally recognisable of the fainter constellations, its stars tracing the goblet's profile closely enough that even observers unfamiliar with the myth can usually see the shape being described.