A Voyage on the Argo
24 May 2017
The epic voyage of Jason and the Argonauts is one of the greatest stories of heroism, intrigue, betrayal, and tragedy. And it is a story that is retold in the stars, in the fragmented remains of the constellation Argo Navis.
Last night I was looking at the great ship Argo Navis navigating the turbulent Milky Way seas, its prow vanishing into a bank of mist, and thinking that it’s a real shame this magnificent and ancient constellation was considered “unwieldy” and dismantled. Of course it was unwieldy… it was a mighty 50-oared galley, carrying some of the greatest Greek heroes, how could it possibly be wieldy?
The story of Jason and the Argonauts and their fabulous ship, the Argo (Greek for “swift”), has been told for 3,000 years. The story is set a generation before the time of the Trojan War, around 1,300 BC, but the first known written mention of it comes six centuries later, in the age of Homer. (Over the ages, the Greeks retold and reinterpreted the story many times, the tale evolving as their knowledge of the physical world increased.)
It’s a classic hero’s quest tale – a sort of ancient Greek Mission Impossible – in which the hero embarks on a perilous sea voyage into an unknown land, with a great task to achieve. The mission: find and bring back the golden fleece, which is hung from a tree in the grove of the Colchian Ares and guarded night and day by a dragon that never sleeps, in order for Jason to reclaim his father’s kingdom of Iolkos from the usurper King Pelias. (Together, the intrepid crew of the Argo were referred to as the Argonauts – Greek: Argonautai , combining the name of the vessel with the Greek word for “sailors”.)
Jason took with him fifty of the greatest Greek heroes, including the twins Castor and Pollux, the legendary musician Orpheus, as well as Argus, the ship’s builder. Even Hercules interrupted his labours to join the gang. With very little ado the heroes cast off and set sail in their fabulous ship for the inevitable, glory or death.
After their epic voyage to a place beyond the edge of the known world began, Jason and the Argonauts returned home victoriously with the golden fleece. Jason consecrated the mighty Argo to Poseidon in the Isthmus of Corinth.
But like opera, Greek myths tend to end in tragedy, and Jason’s triumphant return soon disintegrated into trickery, tragedy, death and destruction at the hands of the gods. In the end Jason became a wanderer, and one day, as an old man, sitting next to the dilapidated hull of his beloved Argo with whom he had shared such fabulous adventures, the glorious and tragic figure asked Zeus to show mercy on him. A lashing snapped and a beam fell on him, ending his life.
His story had come full circle – as in all Greek myths, the hero’s destiny is in the hands of the gods.
The Argo is placed among the stars
Athena placed the Argo in the heavens – as Manilius recorded in his Astronomica, “Then famed Argo, raised to the skies from the sea which it was the first to cross, occupies the heaven it earned through grievous perils in a bygone age, made a god for having given safety to gods.”
Johann Bayer’s Uranographia of 1603 depicted the Argo passing between the Clashing Rocks at the mouth of the Black Sea. Bayer depicts some of the ship’s oars splintering on the rocks, and the yard arm with the furled sail also appears to have snapped. The brilliant star Canopus lies on the blade of the portside steering oar, as described by Ptolemy
Originally, the Argo sailed low across the southern horizon of the Mediterranean sky. The ship became visible in springtime and sailed westward, skimming along the southern horizon, but today, owing to the effects of precession, for Jason’s northern hemisphere stargazing descendants the mighty ship has run aground on the reefs of the horizon.
The fabulous ship appears to have no bow, thus presenting the same sectional character as Equuleus, Pegasus, and Taurus. It also rotates backward across the heavens, trailing behind Sirius.
Lacaille dismantles the Argo
During his famous 1751-1753 expedition to South Africa to chart the southern skies, French astronomer Nicholas Louis de Lacaille decided the ancient constellation was just too large and unwieldy, containing as it did over 160 naked-eye stars, and that the area needed to be divided into smaller, more manageable constellations.
The Argo Navis was such a majestic, traditional image it couldn’t simply be scrapped and replaced by new constellations, so Lacaille compromised. He left the ancient image in the sky, with all its grand mythological romance, and simply divided the figure into the three parts we all know: Carina, the keel, Puppis, the poop deck, Vela, the sail.
It is commonly accepted that despite the division, Lacaille kept Argo’s Bayer designations but in actual fact, as recorded in the 1843 Monthly Notices of the Royal Astronomical Society, he changed them (as he also did in Centauris, Ara and Lupus). Oddly, when he did so, he used just one sequence of Greek letters, from Alpha to Omega, as though Argo were still a single constellation, hence the reason Carina’s brightest star is Alpha, whereas the brightest star in Puppis is Zeta and the brightest in Vela is Gamma.
Last night, after embarking naked eye on that fantastic and perilous voyage with Jason and his friends, I spent the night slowly cruising the vast area of the Argo Navis… what a glorious voyage! If the Scorpius-Sagittarius area of sky delivers the greatest show off earth, then this region is a close second. The entire area is full of astounding deep sky objects, a virtuoso display of nebulosity, rich clusters and beautiful stars.
Observations
10×50 binoculars
It’s tough to winnow all the beauties down for a blog-sized entry, so I decided to record my observations of the fourteen remarkable objects that Lacaille discovered in Puppis, Carina and Vela and recorded in his 1755 Catalogue of Nebulae of the Southern Sky.
And in light of the fact this extraordinary astronomer made his discoveries using his 1/2 inch 8x telescope, I used my 10×50 binoculars to view his objects. I love binocular viewing; after naked eye, I find that the night sky is most intimately viewed while relaxing horizontally with my binos, and it was certainly so on this voyage on the Argo.
PUPPIS:
Lacaille I.3 (NGC 2477) Open Cluster
RA 07 52 06 Dec –38 32 00 Mag 5.8 Size 15′
Lacaille: Large nebulosity of 15′ to 20′ in diameter.
Me: This open cluster is a gorgeous sight. The 10×50 binos show it as a large, slightly-off-round nebulous glow. No stars resolved, just the large puff of glimmering starlight. Averted vision shows a larger, brighter and mistier glow. It looks like the extended glow of a comet, and is made prettier by lying in a pretty barren piece of sky.
Lacaille II.4 (NGC 2546) Open Cluster
RA 08 11 54 Dec –37 37 00 Mag 6.3 Size 70′
Lacaille: Two neighbouring groups of confused stars are seen by the eye but in the telescope they are faint, distinct stars, very numerous and close.
Me: I am not sure what Lacaille meant by “Two neighbouring groups…” as naked eye the cluster looks like a slightly brighter patch of the Milky Way, although north and east of the cluster is a somewhat hazier area. In the binoculars the cluster shows as a beautiful large scattering of very small stars, standing out well against the rich and bright starry background.
CARINA:
Lacaille II.3 (NGC 2516) Open Cluster
RA 07 58 06 Dec –60 45 00 Mag 3.8 Size 30′
Lacaille: Group of 10 to 12 stars, much compressed.
Me: Naked eye, the cluster is clearly visible as a mottled glow just west and slightly south of the tip of the False Cross. In the binoculars it’s a gorgeous sight: a mass of large and small stars filling a vaguely diamond-shape, with a swathe of stardust snaking northwards, and then branching east and west. The visible stars of mixed magnitude lie embedded in a soft silky glow of unresolved starlight, and the entire cluster stands out beautifully against a rich starry background.
Lacaille II.8 (NGC 3293) Open Cluster
RA 10 35 48.8 Dec –58 13 00 Mag 4.7 Size 6′
Lacaille: Small heap of four faint stars forming a lozenge.
Me: An absolutely gorgeous cluster! Small, extremely bright; three stars in a close little chain running northeast-southwest to the middle of the cluster, the southernmost star a beautiful deep orangey-red. There is another bright little star on the northwestern edge of the cluster, and there are many more faint stars making up the cluster, all of them embedded in the bright glow of unresolved starlight. It really is a lovely sight.
Lacaille II.9 (IC 2602) Open Cluster
RA 10 43 12 Dec –64 24 00 Mag – Size 100′
Lacaille: The star Theta Navis, of the third magnitude or less, surrounded by a large number of stars of sixth, seventh and eighth magnitude, which make it resemble the Pleiades.
Me: Visible to the naked eye as a nebulous patch around a bright star it is nothing less than dazzling in binoculars! Its brilliant blue and white stars look like diamonds casually sprinkled on black velvet. It’s a loose collection of stars in two distinct groupings. The western group has at its heart blue supergiant blue Theta Carinae and the stars arranged in a slightly arced curve. The eastern grouping of 5 stars is arranged in a pattern that resembles a square-ish hour glass. Between the two groupings is a distinctly starless strip containing just a few tiny pinprick stars. All in all, a very striking open cluster.
Lacaille II.10 (NGC 3532) Open Cluster
RA 11 05 33 Dec –58 43 48 Mag 3 Size 50′
Lacaille: Prodigious cluster of faint stars, very compressed, filling up in the shape of semi-circle of 20’ to 25’ in diameter.
Me: Clearly visible to the naked eye as a large silky glow, the cluster is a spectacular sight in the binoculars: a vast, very rich cluster of stars in a squashed diamond shape, the long axis east-west. The cluster has strands of stardust that trail out and merge with the very rich Milky Way background. The stars are very uniform in brightness, a lovely swarm of stars, with a lovely bright yellowy-orange star lying southeast of the centre. On the eastern edge is a triangular dark zone, and on the western side is a less prominent irregular dark patch, both of which give definition to the cluster’s shape. In shape and uniformity and mass of stars, it’s not hard to see why this cluster is nicknamed the pincushion cluster.
Lacaille II1.5 & 6 (Carina Nebula)
RA 10 44 19 Dec –59 53 21 Mag – Diam –
Lacaille: (III.5): Two faint stars surrounded by nebulosity.
(III.6): Large group of a great number of faint stars, a little compressed, and occupying the space of a semi-circle of 15’ to 20’ diameter; with a slight nebulosity spreading in that space.
Me: What can I say? It’s one of the skies most spectacular sights. The nebula is easily visible to the naked eye as a large frosty patch. Indeed, it is the brightest patch in the southern Milky Way. And it’s a fabulous sight in binoculars – a beautiful glowing cloud of silky nebulosity cut across by a dark lane of cosmic dust that divides the nebula into one-third, two-third portions. The nebula contains eight open clusters – and although you can’t make them out in binoculars you can certainly see the brighter stars embedded in the glowing nebula… and the crown jewel… Eta Carina itself, a gorgeous smoldering orange star.
VELA
Lacaille II.5 (IC 2391) Open Cluster
RA 08 40 40 Dec –53 03 24 Mag 2.5 Size 60′
Lacaille: Small heap of stars.
Me: Visible to the naked eye as a small glowing cloud of starlight, it is another gorgeous binocular cluster; a dazzler! It shows as a lovely large sprawl of scattered bright stars, with faint stars strewn in and around the scattering of bright stars. The whole cluster is made prettier by the lovely rich field in which the cluster lies.
Lacaille II.6 (Trumpler 10) Open Cluster
RA 08 47 45 Dec –42 30 00 Mag 4.6 Size 29′
Lacaille: Heap of seven or eight stars, slightly compressed.
Me: The cluster lies in a rich starry background and the cluster shows in the binoculars as a lovely, loose, roughly oblong-shaped scattering of five bright stars and five fainter stars, embedded in the misty starlight of unresolved stars.
Lacaille II.7 (NGC 3228) Open Cluster
RA 10 21 24 Dec –51 44 00 Mag 6 Size 5′
Lacaille: Heap of four or five stars, very small and compressed.
Me: ‘Heap’ describes the way the small bright knot of stars look, lying in a rich field. The three brightest stars form a neat little equilateral triangle in the centre of the cluster, with another trio of slightly less bright and smaller stars are visible to the western side of the cluster. Averted vision shows a few more tiny stars.
Lacaille III.2 (NGC 2547) Open Cluster
RA 08 10 26 Dec –49 10 03 Mag 4.7 Size 25′
Lacaille: Five faint stars, in the shape of a T, surrounded by nebulosity.
Me: This is a gorgeous cluster, standing out well against the rich background field. The cluster appears to me more like the shape of a tau as the lovely north-south arc of brighter stars running across the centre of the cluster has a beautiful little curve at the end. A bright, slightly yellowy star lies about one third of the way along the arc. A bar of fainter stars runs across the arc, extending to the northwest. The tau asterism is embedded in a haze of very faint stars and unresolved starlight.
Lacaille II.10 (IC 2395) Open Cluster
RA 08 42 31 Dec –48 08 12 Mag 4.6 Size 18.6′
Lacaille: Star of 6th magnitude, connected to another more southern one by a nebulous trail.
Me: A lovely cluster in the binoculars; the brighter stars arching away from the lucida in a hazy puff of mottled starlight that spreads out like a comet’s tail to the southwest. The cluster lies in a beautiful star-rich field.
Lacaille III.4 (IC 2488) Open Cluster
RA 09 27 36 Dec –57 00 00 Mag 7.4 Size 18′
Lacaille: Faint star surrounded by nebulosity.
Me: The cluster appears as a delightfully delicate cloud-like cluster of pinprick stars; the southeastern section containing a short, snug little row of faint stars with a single prominent star further southeast. The rest of the clusters appears to spray off as a nebulous cloud of starlight to the northwest.
Copyright © Susan Young 2017