Constellation Close-up Argo Navis
OF THE 48 CONSTELLATIONS DESCRIBED in Claudius Ptolemy’s Almagest, 47 survive to the current day. The sole exception is Argo Navis, the ship that carried the mythical Greek hero Jason and his fellow Argonauts to the end of the known world in quest of the Golden Fleece. Its stars ended up distributed among four nautically themed constellations: Carina, the keel or hull; Vela, thes Sails; Puppis, the poop deck; and Pyxis, the compass. Pyxis is small and dim, but Carina, Vela and Puppis are all big, bright, and spangled with naked-eye star clusters. If you put them back together, they’d be the biggest constellation in the sky — much bigger than Ptolemy’s original Argo, in fact. For shorthand, I will call the original constellation Old Argo Navis, and use Greater Argo Navis to denote modern Carina, Vela and Puppis.
The standard explanation for Argo Navis’s dismemberment is that the French astronomer Nicolas-Louis de Lacaille (1713–62) chopped it up — and there is some truth to that. It’s a fair bet that the constellation would still be alive and well today if Lacaille hadn’t sailed to South Africa to observe the southern skies. Lacaille did indeed slice Pyxis off Argo, but he used the terms Carina, Vela and Puppis only to describe aspects of Greater Argo Navis. He would have been horrified to know that they would end up replacing it. Lacaille doomed Argo to extinction not because he despised it but because he loved it too much.
Another way to view Argo’s demise is that it resulted from impersonal forces: the globalisation of European culture, the invention of the telescope, and the rising power of science and innovation with respect to tradition and authority.
Argo Navis is a southerly constellation, making it particularly vulnerable to the change in perspective — both physical and cultural — that marked the advent of the modern Western world. The southernmost stars of Old Argo were barely visible from the
