Messier 46 or M46, also known as NGC 2437, is an open cluster of stars in the constellation of Puppis. This image was taken on February 4, 2019 from my Creedmoor site. M46 was discovered by Charles Messier in 1771. Dreyer described it as "very bright, very rich, very large." M46 is about 4,920 light-years away. There are an estimated 500 stars in the cluster with a combined mass of 453 M☉, and it is thought to be some 251.2 million years old.
The cluster has a tidal radius of 37.8 ± 4.6 ly (11.6 ± 1.4 pc) and a core radius of 8.5 ± 1.3 ly (2.6 ± 0.4 pc).
The planetary nebula NGC 2438 appears to lie within the cluster near its northern edge (the faint smudge at the top center of the image), but it is most likely unrelated since it does not share the cluster's radial velocity. It is an example of a superimposed pair possibly similar to that of NGC 2818.