Argo Navis (the Ship Argo), or simply Argo, is one of the 48 Ptolemy's constellations, now a grouping of three IAU constellations. It is formerly a single large constellation in the southern sky. The genitive is "Argus Navis", abbreviated "Arg". 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) 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." Due to precession of the equinoxes, the position of the stars from Earth's viewpoint has shifted southward, and 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. History Development of the Greek constellation Argo Navis is known from Greek texts, which derived it from Egypt around 1000 BC. Plutarch attributed it to the Egyptian "Boat of Osiris." Some academics theorized a Sumerian origin related to the Epic of Gilgamesh, a hypothesis rejected for lack of evidence that Mesopotamian cultures considered these stars, or any portion of them, to form a boat. Over time, Argo became identified exclusively with ancient Greek myth of Jason and the Argonauts. In Ptolemy's Almagest, Argo Navis occupies the portion of the Milky Way between Canis Major and Centaurus, with stars marking such details as the "little shield", the "steering-oar", the "mast-holder", and the "stern-ornament", which continued to be reflected in cartographic representations in celestial atlases into the nineteenth century (see below). The ship appeared to rotate about the pole sternwards, so nautically in reverse. Aratus, the Greek poet / historian living in the third century BCE, noted this backward