Puppis - The Stern of the Argo

Puppis is visible in the southern sky from January until May. It is a winter constellation for observers in the northern hemisphere. It is located southeast of Canis Major. While Puppis does not have a very recognizable figure, it does contain many bright stars. With the Milky Way running through its northern half, Puppis contains many interesting deep sky objects.

History and Mythology

Puppis was part of an ancient constellation, Argo Navis, that was divided into four smaller constellations by the astronomer Nicholas Louis de Lacaille in the 1700s. The new constellations were Puppis (the Stern), Carina (the Keel), Vela (the Sails), and Pyxis (the Compass).

Greek myth tells us that the Argo and her crew of 50, with Jason as Captain, set out on a journey to bring back the fleece of a winged golden ram. This is one of the most famous of the Greek myths. Jason's wicked uncle sent him to Colchis to bring back the golden fleece from the sacred grove guarded by a fierce dragon.

Jason called upon his childhood friends to join him. They traveled past a land of six-handed giants and then on to Asia Minor. They traveled between clashing rocks that wandered into the sea, and past the place where Prometheus was chained and tormented by an eagle for stealing the gods' fire. When the Argonauts finally reached Colchis, they entered through woods where dead men hung from trees. Jason met Medea, the daughter of the king, and she fell in love with him. She helped him win the golden fleece, and returned with the Argonauts to Greece. While planning to take the golden fleece, the Argonauts killed Medea's brother to keep him from telling of their plans. Their punishment was that they would never find peace.

Notable Stars

Zeta Puppis or Naos, whose Greek name means "ship", is a brilliant, blue-white, 2nd magnitude star about 970 light-years away. It is one of the hottest stars known, with a surface temperature of 42,000 degrees. Xi Puppis, also known as Asmidiske, is a yellow supergiant of 3rd magnitude, about 1300 light-years away.

L2 Puppis is one of the brightest pulsating Mira-type variable stars in the sky, and varies between magnitude 2.6 and 6.2 over a 141-day cycle.

Clusters, Nebulae, and Galaxies

An 8 inch telescope will show many interesting objects in Puppis. In the northern part of the constellation is M 46, an open cluster with over 100 stars of 9th magnitude and fainter. With a small telescope, it looks like a sprinkling of star dust. Appearing within the cluster is the 11th magnitude planetary nebula NGC 2438, but this is a foreground object less than half the cluster's distance away, and is physically unrelated to the cluster stars.

Just west of M 46 is the open cluster M 47, which can be seen with the naked eye. It contains about 30 stars of 6th magnitude and fainter. M 93 is a 6th magnitude cluster containing 80 stars of 8th magnitude and fainter. NGC 2298 is a globular cluster of 10th magnitude. This cluster is found on the western side of Puppis, near the border with Columba.

South of M 46 and M 47 is an 11th magnitude planetary nebula, NGC 2440. NGC 2477 is a rich 6th-magnitude open cluster in Puppis, containing several hundred stars of 10th magnitude and fainter. NGC 2467 is a diffuse nebula of 8th magnitude. There are no galaxies brighter than 12th magnitude in Puppis.