Puppis

The constellation Puppis rows low across the southern sky on early-spring evenings. It represents the stern of the Argo, the boat that carried Jason and the Argonauts through many harrowing adventures.

Most of the constellation’s stars are faint. In fact, its leading light barely ranks among the 70 brightest stars of the night sky.

In most constellations - especially those from the ancient world - that star would have a name beginning with “alpha,” the first letter of the Greek alphabet, so it’d be known as Alpha Puppis. In this case, though, the star is known as Zeta Puppis - the sixth letter of the alphabet.

That naming system was devised by astronomer Johann Bayer more than four centuries ago. He generally gave the “alpha” designation to a constellation’s brightest star. The rest of the stars were labeled based on their brightness or their position in the sky.

At the time Bayer came up with his system, though, Puppis didn’t exist. Instead, it was part of the much larger constell