| Constellation | |
   | |
| Abbreviation | Arg |
|---|---|
| Genitive | Argus Navis/Argus/Navis |
| Symbolism | The Ship Argo |
| Right ascension | 7.5h –11h |
| Declination | 30° – 75° |
| Area | 1667 sq. deg. |
| Main stars | 32 |
| Bayer/Flamsteed stars | 178 |
| Stars withplanets | 24 |
| Stars brighter than 3.00m | 12 |
| Stars within 10.00 pc (32.62 ly) | 7 |
| Brightest star | Canopus (α Arg) (−0.74m) |
| Messier objects | 3 |
| Meteor showers | |
| Bordering constellations | |
| Visible at latitudes between +20° and −90°. Best visible at 21:00 (9 p.m.) during the month ofFebruary-March. | |
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Argo Navis (the Ship Argo), or simplyArgo, is one of Ptolemy's 48 constellations, now a grouping of threeIAU constellations. It was formerly a single largeconstellation in thesouthern sky. The genitive is "Argus Navis", abbreviated "Arg".John Flamsteed and other early modern astronomers called itNavis (the Ship), genitive "Navis", abbreviated "Nav".
The constellation proved to be of unwieldy size, as it was 28% larger than thenext largest constellation and had more than 160 easily visible stars. The 1755 catalogue ofNicolas 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), andVela (the sails).
Argo derived from the shipArgo inGreek mythology, sailed byJason and theArgonauts toColchis in search of theGolden Fleece.[1] Some stars of Puppis and Vela can be seen fromMediterranean latitudes in winter and spring, the ship appearing to skim along the "river of theMilky Way."[2] Theprecession 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.[3] 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 isCanopus (α Carinae), the second-brightest night-time star, now assigned to Carina.
Argo Navis is known from Greek texts, which derived it fromEgypt around 1000 BC.[4]Plutarch attributed it to the Egyptian "Boat ofOsiris."[4] Some academics theorized aSumerian origin related to theEpic of Gilgamesh, a hypothesis rejected for lack of evidence thatMesopotamian cultures considered these stars, or any portion of them, to form a boat.[4]
Over time, Argo became identified exclusively with ancient Greek myth ofJason and theArgonauts. InPtolemy'sAlmagest, Argo Navis occupies the portion of the Milky Way betweenCanis Major andCentaurus, with stars marking such details as the "little shield", the "steering-oar", the "mast-holder", and the "stern-ornament",[5] 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 progression writing, "Argo by theGreat Dog's [Canis Major's] tail is drawn; for hers is not a usual course, but backward turned she comes ...".[6]
In modern times, Argo Navis was considered unwieldy due to its enormous size (28% larger thanHydra, the largest modern constellation).[1] In his 1763 star catalogue,Nicolas Louis de Lacaille explained that there were more than a hundred and sixty stars clearly visible to the naked eye in Navis. So he used the set of lowercase and uppercase Latin letters three times on portions of the constellation referred to as "Argûs in carina" (Carina, thekeel), "Argûs in puppi" (Puppis, thepoop deck orstern), and "Argûs in velis" (Vela, thesails).[7] Lacaille replaced Bayer'sdesignations with new ones that followed stellar magnitudes more closely, but used only a single Greek-letter sequence and described the constellation for those stars as "Argûs". Similarly, faint unlettered stars were listed only as in "Argûs".[8]
The final breakup and abolition of Argo Navis was proposed bySir John Herschel in 1841 and again in 1844.[9] Despite this, the constellation remained in use in parallel with its constituent parts into the 20th century. In 1922, along with the other constellations, it received a three-letter abbreviation:Arg.[10] The breakup and relegation to aformer constellation occurred in 1930 when the IAU defined the88 modern constellations, formally institutingCarina,Puppis, andVela, and declaringArgo obsolete.[11] Lacaille's designations were kept in the offspring, soCarina hasα,β, andε;Vela hasγ andδ;Puppis hasζ; and so on.[12]: 82 As a result of this breakup, Argo Navis is the only one of Ptolemy's 48 constellations that is no longer officially recognized as a single constellation.[13]
In addition, the constellationPyxis (themariner's compass) occupies an area near what in antiquity was considered part of Argo's mast. Some recent authors state that the compass was part of the ship,[14][15] but magnetic compasses were unknown in ancient Greek times.[1] Lacaille considered it a separate constellation representing a modern scientific instrument (likeMicroscopium andTelescopium), that he created for maps of the stars of the southern hemisphere. Pyxis was listed among his 14 new constellations.[a][8][12]: 262 In 1844, John Herschel suggested formalizing the mast as a new constellation,Malus, to replace Lacaille'sPyxis, but the idea did not catch on.[1] Similarly, an effort byEdmond Halley to detach the"cloud of mist" at the prow of Argo Navis to form a new constellation namedRobur Carolinum (Charles' Oak) in honor ofKing Charles II, his patron, was unsuccessful.[16]
InVedic period astronomy, which drew its zodiac signs and many constellations from the period of theIndo-Greek Kingdom, Indian observers saw the asterism as a boat.[17]
TheMāori had several names for the constellation, includingTe Waka-o-Tamarereti (the canoe of Tamarereti),[18]Te Kohi-a-Autahi (an expression meaning "cold of autumn settling down on land and water"),[19] andTe Kohi.[20]
Constellation ofArgo Navis | |||||||||||||||||||||||||||||||||||||||||||||||||
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| Argo Navis Bayer stars | |||||||||||||||||||||||||||||||||||||||||||||||||
Stars of constellations, comprising formerArgo Navisconstellation: | |||||||||||||||||||||||||||||||||||||||||||||||||
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Note:Pyxis constellation is considered as a part ofArgo ship, but may not considered as a part ofArgo Navis former constellation. | |||||||||||||||||||||||||||||||||||||||||||||||||
