Crater

Crater shares its myth with Corvus and Hydra, the crow, the serpent and the cup set together as a lasting rebuke. What the shared story does not mention is how thoroughly empty the cup itself has turned out to be by the standards of later astronomy.

Crater contains no star brighter than roughly fourth magnitude and no object at all from Charles Messier's eighteenth-century catalogue of nebulae and star clusters, an unusual gap among Ptolemy's forty-eight and one that has kept the constellation essentially absent from the deep-sky observing tradition that grew up around brighter, richer neighbours. Where Corvus, sitting right beside it, hosts colliding galaxies bright enough to be studied in detail, and Hydra beneath it holds an entire cluster of distant galaxies, Crater offers modern telescopes very little beyond the outline itself.

That outline remains, by most accounts, one of the more literally recognisable of the fainter constellations, its handful of modest stars tracing a wide, shallow bowl closely enough that the shape reads clearly even to someone unfamiliar with the myth behind it.

A cup that carries a story about being kept perpetually unfilled has turned out, by coincidence, to be one of the emptiest patches of sky in the whole catalogue by the measure later astronomers actually use.

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.