Hydra constellation. Illustrated card from a 19th century astronomical teaching aid called Urania's Mirror, after the Greek muse of astronomy. This card shows the constellations Noctua (the owl; obsolete), Corvus (the crow), Crater (the cup), Sextans (the sextant, an astronomical navigational tool, also called Sextans Uraniae), Hydra (a serpent-like monster from Greek mythology), Felis (the cat; obsolete), Lupus (the wolf), Centaurus (the centaur, a horse-man hybrid), Antlia (the pump, here called the pneumatic pump), Argo Navis (the Argo, a ship from Greek mythology; obsolete), and Pyxis (the box or nautical compass). For the full set of 32 cards, see V700/172-203.