Argo Navis

Argo Navis (the Ship Argo), or simply Argo, is one of Ptolemy's 48 constellations, now a grouping of three IAU constellations. It was formerly a single large constellation in the southern sky. The genitive is "Argus Navis", abbreviated "Arg". John Flamsteed and other early modern astronomers called it Navis (the Ship), genitive "Navis", abbreviated "Nav". The constellation proved to be of unwieldy size, as it was 28% larger than the next largest constellation and had more than 160 easily visible stars. The 1755 catalogue of Nicolas Louis de Lacaille divided it into the three modern constellations that occupy much of the same area: Carina (the keel), Puppis (the poop deck or stern), and Vela (the sails). Argo derived from the ship Argo in Greek mythology, sailed by Jason and the Argonauts to Colchis in search of the Golden Fleece. Some stars of Puppis and Vela can be seen from Mediterranean latitudes in winter and spring, the ship appearing to skim along the "river of the Milky Way." The precession of the equinoxes has caused the position of the stars from Earth's viewpoint to shift southward. Though most of the constellation was visible in Classical times, the constellation is now not easily visible from most of the northern hemisphere. All the stars of Argo Navis are easily visible from the tropics southward and pass near zenith from southern temperate latitudes. The brightest of these is Canopus (α Carinae), the second-brightest night-time star, now assigned to Carina.