Argo is a constellation that is not so much disused as dismantled. It was one of
the 48 constellations known to Greek astronomers, as listed by Ptolemy in the Almagest, but astronomers in the 18th century found it large and unwieldy and so divided
it into three parts: Carina, the Keel or body, Puppis, the Poop (i.e. stern), and Vela, the Sails. Were the three parts to be reunited, the resulting figure would be
almost 28% larger in area than the current largest constellation, Hydra. The
modern constellation Pyxis, the compass, occupies an area next to the mast, but is not considered a part
of the original Argo. In 1844 the English astronomer John Herschel proposed replacing Pyxis with a fourth subdivision of Argo which he called Malus, the mast, but this
suggestion was not widely adopted.
Argo Navis represents the 50-oared galley in which Jason and the Argonauts
sailed to fetch the golden fleece from Colchis in the Black Sea. Jason
entrusted the building of the ship to Argus, after whom it was named. Argus
built the ship under the orders of the goddess Athene at the port of Pagasae,
using timber from nearby Mount Pelion. Into the prow Athene fitted an oak beam
from the oracle of Zeus at Dodona in north-western Greece. This area, like the
island of Corfu nearby, was once noted for its forests of oak, before later
shipbuilders stripped them bare. Being part of an oracle, this oak beam could
speak and it was crying out for action by the time the Argo left harbour.
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Argo Navis dominates this crowded scene in the southern celestial hemisphere in the Uranographia of Johann Bode (1801). On the blade of one of the steering oars lies the bright star Canopus, now part of the constellation Carina.
The prow of the ship was usually imagined as disappearing between the Clashing
Rocks or vanishing into the mists of the Milky Way, but here the rocks are
replaced by Charles’s Oak (Robur Caroli II), a now-obsolete constellation invented by Edmond Halley.
Unlike other depictions of Argo, this version has no main mast rising from the
body of the ship. The spar around which the sail is wrapped appears to emerge
from the stern, but this may be an artistic error.
Because of Argo’s considerable size, cartographers struggled to depict it successfully on a
single chart. The attempt by Bode above is perhaps the best, but for some
alternative views click here.
Jason took with him 50 of the greatest Greek heroes, including the twins Castor
and Polydeuces, the musician Orpheus, as well as Argus, the ship’s builder. Even Heracles interrupted his labours to join the crew.
Apollonius of Rhodes, who wrote the epic story of the ship’s voyage to Colchis and back, described Argo as the finest ship that ever braved
the sea with oars. Even in the roughest of seas the bolts of Argo held her
planks together safely, and she ran as sweetly when the crew were pulling at
the oars as she did before the wind. Isaac Newton thought the voyage of the
Argo was commemorated in the 12 signs of the zodiac, although the connections
are hard to see.
Among the greatest dangers the Argonauts faced en route were the Clashing Rocks,
or Symplegades, which guarded the entrance to the Black Sea like a pair of
sliding doors, crushing ships between them. As the Argonauts rowed along the
Bosporus, they could hear the terrifying clash of the Rocks and the thunder of
surf. The Argonauts released a dove and watched it fly ahead of them. The Rocks
converged on the dove, nipping off its tail feathers, but the bird got through.
Then, as the Rocks separated, the Argonauts rowed with all their might. A
well-timed push from the divine hand of Athene helped the ship through the
Rocks just as they slammed together again, shearing off the mascot from Argo’s stern. Argo had become the first ship to run the gauntlet of the Rocks and
survive. Thereafter the Clashing Rocks remained rooted apart.
Once safely into the Black Sea, Jason and the Argonauts headed for Colchis.
There they stole the golden fleece from King Aeëtes, and made off with it back to Greece by a roundabout route. After their
return, Jason left the Argo beached at Corinth, where he dedicated it to
Poseidon, the sea god.
Eratosthenes said that the constellation represents the first ocean-going ship
ever built, and the Roman writer Manilius concurred. However, this attribution
must be wrong because the first ship was actually built by Danaus, father of
the 50 Danaids, again with the help of Athene, and he sailed it with his
daughters from Libya to Argos.
Argo in the sky
Only the stern of Argo is shown in the sky. Map makers attempted to account for
this truncation either by depicting its prow vanishing into a bank of mist, as
Aratus described it, or by passing between the Clashing Rocks, as shown on Bayer’s atlas. Robert Graves recounts the explanation that Jason in his old age returned to
Corinth where he sat beneath the rotting hulk of Argo, contemplating past
events. Just at that moment the rotten beams of the prow fell off and killed
him. Poseidon then placed the rest of the ship among the stars. Hyginus,
though, says that Athene placed Argo among the stars from steering oars to sail
when the ship was first launched, but says nothing about what happened to the
prow.
Argo was first subdivided into Carina, Puppis and Vela by the French astronomer Nicolas Louis de Lacaille in his catalogue of the southern stars published in 1756 and it now lies
permanently dismembered. There is, though, still an echo of its former unity.
Lacaille was dissatisfied with Bayer’s allocation of Greek letters to the stars of Argo, so he decided to change
them. However, when he did so, he used just one sequence of Greek letters, from
Alpha to Omega, as though Argo were still a single figure. The designations
Alpha and Beta were given to the two brightest stars of Argo, which are in
Carina; hence there are no stars labelled Alpha or Beta in either Puppis or
Vela. Equally, the brightest star in Puppis is Zeta and the brightest in Vela
is Gamma, but there is no Zeta or Gamma Carinae.
© Ian Ridpath. All rights reserved
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