Argo Navis
Formerly a single large constellation, now divided into Carina, Puppis, and Vela.
Argo Navis, also called the Ship Argo or simply Argo, was one of the 48 constellations listed by Ptolemy and is now represented by three modern constellations recognized by the International Astronomical Union (IAU). Originally a single, enormous constellation in the southern sky, it was 28% larger than the next largest constellation and contained over 160 stars easily visible to the naked eye. It is the only one of Ptolemy's original 48 constellations that is no longer officially considered a single constellation. Its genitive form is "Argus Navis," abbreviated "Arg"; early modern astronomers like John Flamsteed referred to it simply as Navis, with the genitive "Navis" and abbreviation "Nav."
Because of its unwieldy size, the French astronomer Nicolas Louis de Lacaille divided Argo Navis into three modern constellations in his 1755 star catalogue: Carina (the keel), Puppis (the poop deck or stern), and Vela (the sails). These three constellations now occupy much of the same area of the sky. The constellation's name comes from the ship Argo in Greek mythology, which carried Jason and the Argonauts to Colchis in search of the Golden Fleece. From Mediterranean latitudes, some stars of Puppis and Vela are visible in winter and spring, with the ship appearing to skim along the Milky Way. Due to the precession of the equinoxes, the stars have shifted southward from Earth's perspective; while most of the constellation was visible in classical times, it is now difficult to see from most of the northern hemisphere. All its stars are easily seen from the tropics southward and pass near the zenith from southern temperate latitudes. The brightest star in Argo Navis is Canopus (α Carinae), the second-brightest star in the night sky, now assigned to Carina.
The Greek constellation of Argo Navis is known from texts that trace it back to Egypt around 1000 BC. Plutarch linked it to the Egyptian "Boat of Osiris." Some scholars have proposed a Sumerian origin connected to the Epic of Gilgamesh, but this idea is rejected due to a lack of evidence that Mesopotamian cultures saw these stars as forming a boat. Over time, Argo became exclusively associated with the Greek myth of Jason and the Argonauts.
Quick Facts
- Abbreviation
- Arg
- Genitive
- Argus Navis/Argus/Navis
- Symbolism
- The Ship Argo
- Ra
- 7.5 – 11
- Dec
- 30 – 75
- Areatotal
- 1667
- Numbermainstars
- 32
- Numberbfstars
- 178
- Numberstarsplanets
- 24
- Numberbrightstars
- 12
- Numbernearbystars
- 7
- Brighteststarname
- Canopus (α Arg)
Facts from the source article.
Lore & Background
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. Over time, Argo became identified exclusively with the 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 details such as the 'little shield', the 'steering-oar', the 'mast-holder', and the 'stern-ornament.' The ship appeared to rotate about the pole sternwards, so nautically in reverse. Aratus noted this backward progression writing, 'Argo by the Great Dog's tail is drawn; for hers is not a usual course, but backward turned she comes ...'.
Reader's Guide
In modern times, Argo Navis was considered unwieldy due to its enormous size. In his 1763 star catalogue, Nicolas Louis de Lacaille divided it into three portions: Carina (the keel), Puppis (the poop deck or stern), and Vela (the sails), using a single Greek-letter sequence for stars described as 'Argûs'. The final breakup and abolition was proposed by Sir John Herschel in 1841 and again in 1844, but the constellation remained in use in parallel with its constituent parts into the 20th century. In 1922 it received a three-letter abbreviation: Arg. The breakup occurred in 1930 when the IAU defined the 88 modern constellations, formally instituting Carina, Puppis, and Vela, and declaring Argo obsolete. Lacaille's designations were kept in the offspring, so Carina has α, β, and ε; Vela has γ and δ; Puppis has ζ; and so on. The constellation Pyxis (the mariner's compass) occupies an area near what in antiquity was considered part of Argo's mast, but Lacaille considered it a separate constellation representing a modern scientific instrument. In 1844, John Herschel suggested formalizing the mast as a new constellation, Malus, to replace Lacaille's Pyxis, but the idea did not catch on. An earlier effort by Edmond Halley to detach the 'cloud of mist' at the prow to form Robur Carolinum was ultimately unsuccessful.
Did You Know?
- It is the only one of Ptolemy's 48 constellations no longer officially recognized as a single constellation.
- The brightest star in Argo Navis is Canopus, the second-brightest night-time star.
- In Vedic period astronomy, Indian observers saw the asterism as a boat.
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