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 with planets | 24 |
Stars brighter than 3.00m | 12 |
Stars within 10.00 pc (32.62 ly) | 7 |
Brightest star | Canopus (α Arg) (−0.74 m ) |
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 of February-March. |
Argo Navis (the Ship Argo), or simply Argo, is one of Ptolemy's 48 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". 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. [1] 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." [2] 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. [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 is Canopus (α Carinae), the second-brightest night-time star, now assigned to Carina.
Argo Navis is known from Greek texts, which derived it from Egypt around 1000 BC. [4] Plutarch attributed it to the Egyptian "Boat of Osiris." [4] 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. [4]
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", [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 the Great 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 than Hydra, 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, and 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, the keel), "Argûs in puppi" (Puppis, the poop deck or stern), and "Argûs in velis" (Vela, the sails). [7] Lacaille replaced Bayer's designations 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 by Sir 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 a former constellation occurred in 1930 when the IAU defined the 88 modern constellations, formally instituting Carina, Puppis, and Vela, and declaring Argo obsolete. [11] 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. [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 constellation Pyxis (the mariner'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 (like Microscopium and Telescopium ), 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's Pyxis, but the idea did not catch on. [1] Similarly, an effort by Edmond Halley to detach the "cloud of mist" at the prow of Argo Navis to form a new constellation named Robur Carolinum (Charles' Oak) in honor of King Charles II, his patron, was unsuccessful. [16]
In Vedic period astronomy, which drew its zodiac signs and many constellations from the period of the Indo-Greek Kingdom, Indian observers saw the asterism as a boat. [17]
The Māori had several names for the constellation, including Te 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] and Te Kohi. [20]
Antlia is a constellation in the Southern Celestial Hemisphere. Its name means "pump" in Latin and Greek; it represents an air pump. Originally Antlia Pneumatica, the constellation was established by Nicolas-Louis de Lacaille in the 18th century. Its non-specific (single-word) name, already in limited use, was preferred by John Herschel then welcomed by the astronomic community which officially accepted this. North of stars forming some of the sails of the ship Argo Navis, Antlia is completely visible from latitudes south of 49 degrees north.
A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas Uranometria. Bayer catalogued only a few stars too far south to be seen from Germany, but later astronomers supplemented Bayer's catalog with entries for southern constellations.
Carina is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was the southern foundation of the larger constellation of Argo Navis until it was divided into three pieces, the other two being Puppis, and Vela.
Abbé Nicolas-Louis de Lacaille, formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good Hope in present-day South Africa. Lacaille observed over 10,000 stars using a refracting telescope.
Pyxis is a small and faint constellation in the southern sky. Abbreviated from Pyxis Nautica, its name is Latin for a mariner's compass. Pyxis was introduced by Nicolas-Louis de Lacaille in the 18th century, and is counted among the 88 modern constellations.
Puppis ("stern") is a constellation in the southern sky. It was originally part of the traditional constellation of Argo Navis, which was divided into three parts, the other two being Carina, and Vela. Puppis is the largest of the three constellations in square degrees. It is one of the 88 modern constellations recognized by the International Astronomical Union.
Vela is a constellation in the southern sky, which contains the Vela Supercluster. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star Gamma Velorum, one component of which is the closest and brightest Wolf-Rayet star in the sky. Delta and Kappa Velorum, together with Epsilon and Iota Carinae, form the asterism known as the False Cross. 1.95-magnitude Delta is actually a triple or quintuple star system.
Columba is a faint constellation designated in the late sixteenth century, remaining in official use, with its rigid limits set in the 20th century. Its name is Latin for dove. It takes up 1.31% of the southern celestial hemisphere and is just south of Canis Major and Lepus.
In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky bordered by arcs of right ascension and declination, together covering the entire celestial sphere. Their boundaries were officially adopted by the International Astronomical Union in 1928 and published in 1930.
The Catasterismi or Catasterisms is a lost work by Eratosthenes of Cyrene. It was a comprehensive compendium of astral mythology including origin myths of the stars and constellations. Only a summary of the original work survives, called the Epitome Catasterismorum, by an unknown author sometimes referred to as pseudo-Eratosthenes.
Omicron Velorum is a star in the constellation Vela. It is the brightest member of the loose naked eye open cluster IC 2391, also known as the ο Velorum Cluster.
Former constellations are old historical Western constellations that for various reasons are no longer widely recognised or are not officially recognised by the International Astronomical Union (IAU). Prior to 1930, many of these defunct constellations were traditional in one or more countries or cultures. Some only lasted decades but others were referred to over many centuries. All are now recognised only for having classical or historical value. Many former constellations had complex Latinised names after objects, people, or mythological or zoological creatures. Others with unwieldy names were shortened for convenience. For example, Scutum Sobiescianum was reduced to Scutum, Mons Mensae to Mensa, and Apparatus Sculptoris to Sculptor.
k Puppis is a Bayer designation given to an optical double star in the constellation Puppis, the two components being k1 Puppis and k2 Puppis.
Constellation families are collections of constellations sharing some defining characteristic, such as proximity on the celestial sphere, common historical origin, or common mythological theme. In the Western tradition, most of the northern constellations stem from Ptolemy's list in the Almagest, and most of the far southern constellations were introduced by sailors and astronomers who traveled to the south in the 16th to 18th centuries. Separate traditions arose in India and China.
Omicron Puppis (ο Puppis) is candidate binary star system in the southern constellation of Puppis. It is visible to the naked eye, having a combined apparent visual magnitude of +4.48. Based upon an annual parallax shift of 2.30 mas as seen from Earth, it is located roughly 1,400 light years from the Sun.
Urania's Mirror; or, a view of the Heavens is a set of 32 astronomical star chart cards, first published in November 1824. They are illustrations based on Alexander Jamieson's A Celestial Atlas, but the addition of holes punched in them allow them to be held up to a light to see a depiction of the constellation's stars. They were engraved by Sidney Hall, and were said to be designed by "a lady", but have since been identified as the work of the Reverend Richard Rouse Bloxam, an assistant master at Rugby School.