NGC 2477 is a rich open cluster in Puppis, containing several hundred stars of 10th magnitude and fainter.
This cluster was discovered by Abbe Lacaille from South Africa during 1751-1752. Burnham states this is "probably the finest of the galactic clusters in Puppis," but it is not in Messier's catalog, as it situated far to the south.
Where it appears sufficiently high above the horizon, NGC 2477 is a splendid, rich cluster of over 300 stars, crowded into a 25' field. Its appearance is very similar to a highly resolved globular cluster, but without a concentrated core. The southern section, which has many star clumps and star chains, is clearly the richest part. Despite the plethora of dim stars, as faint as 14th magnitude, the overall visual magnitude of the cluster is a bright 5.8.
NGC 2477 appears about 2.5° NW from the magnitude 2.25, extremely hot O5 supergiant Zeta Puppis. This star, at 2,400 light years distance, is one of the brightest stars known, with an absolute magnitude of -7.1, corresponding to 60,000 solar luminosities. ζ Pup is unrelated the cluster, which is actually much futher away at 4,200 light years. The brightest star in NGC 2477 is of magnitude 9.81, the hottest of spectral type B8. The cluster's age has been estimated at about 700 million years.