Puppis, "The Stern", is the largest constellation
associated with the former constellation "Argo Navis", the Argonauts' Ship.
It was Nicolas Louis de Lacaille who dismantled the older constellation
in the mid-eighteenth century, breaking it into four smaller constellations:
Carina, Pyxis, Puppis, and Vela.
Not only quite large, the constellation spans a rich area of the Milky
Way, guaranteeing the amateur astronomer a number of fine objects to study.
Since the constellation is part of an older one, it has few Bayer stars.
9 Puppis is a very close binary with rapid orbit
of only 23.18 years. Currently the values are: 5.6, 6.2; PA 315º,
k1 Puppis and k2 Puppis form a noted
system of nearly equal stars: 4.5, 4.7; PA 318º, separation 9.9".
Note that the name here is "k" not "kappa"; many of Puppis' stars are
Rho Puppis is a delta Scuti type variable: 2.68 to 3.87 every
L2 Puppis is a noted semi-regular variable with a wide
range, from 2.6 to 6.2 about every 141 days. This is a giant reg star
150 light years away. Note that the label carries a sub rather
than the normal super..., although some references do not follow the
majority in this matter.
Its unrelated neighbour, L1, is an alpha CV variable: 4.86 to
4.93, every 22h.
Deep Sky Objects:
Puppis has three Messiers and several more deep sky objects of interest.
M46 (NGC 2437) is a fine open cluster of perhaps five hundred
stars about 4000-5000 light years away. Sitting on the northern edge of
the cluster is a planetary nebula, NGC 2438, which is about 3000 light
The cluster is found in the northern portion of the constellation, eleven degrees east of Sirius (alpha CMa) and two degrees north.
M47 (NGC 2422) is a bright open cluster in the same field as M46, just one degree west of M46. Of the two, M47 is the brighter, as it includes several fifth and sixth magnitude stars.
M93 (NGC 2447) is another open cluster, quite bright but smaller
than the two previous objects. It's found 1.5 degrees NW of xi Puppis
NGC 2477 is a very fine globular cluster three degrees NW of zeta
Puppis, nearly half way between pi Puppis and zeta Puppis.
For a more detailed appreciation of Puppis, visit the Binocular Section.