Argo Navis is a large constellation in the southern sky, representing the ship used by the Argonauts in Greek mythology. It was first cataloged by the astronomer Johannes Hevelius in the 17th century and is one of the largest constellations, covering a significant area of the celestial sphere. Due to its size, Argo Navis was later divided into three smaller constellations: Carina (the Keel), Puppis (the Stern), and Vela (the Sails). These divisions help astronomers identify specific regions within the original constellation, making it easier to locate stars and celestial objects in the night sky.