Pyxis, constellation in the southern sky at about 9 hours right ascension and 30° south in declination. Its brightest star is Alpha Pyxidis, with a magnitude of 3.7. The French astronomer Nicolas Louis de Lacaille formed this constellation in 1754 from stars near what was considered the mast of Argo Navis, the constellation that represented the ship that carried Jason and the Argonauts in search of the Golden Fleece. Pyxis represents a ship’s compass.