Clear nights have been tough to come by recently, so when the forecast called for clearing last night, I quickly searched for targets that would stand up to the gibbous moon when shot through my stock Nikon D5300. I happened upon the interesting field below, located in the constellation Puppis. The field contains four open clusters and a neat little planetary nebula. Let me take you on a quick tour.
The well defined cluster at the lower left corner of the image is M46. About a quarter of a billion years old, the cluster is located about 5,000 light years from us. Superimposed on the cluster, on its northern edge, is the planetary nebula NGC 2438. While the nebula appears to be part of the cluster, it is, in fact, considerably closer to us, about 1,370 light years away. Like many planetary nebulae, it has a multi-shell structure. If you take a look at the full-resolution version of the image on Astrobin, you will be able to see some pink nebulosity on the perimeter of the inner, blue nebulosity. This pink nebulosity is actually a semi-detached shell, distinct from the inner, blue shell. Not picked up in my data is a halo of red nebulosity that surrounds the blue-and-pink gaseous ball.
The bright cluster to the lower right of the image is M47. This cluster is relatively young, only 78 million years old. It lies about 1,600 light years away.
Sandwiched between M46 and M47, at the bottom of the image, is the small, old open cluster NGC 2425. This cluster is about 2.5 billion years old. Its advanced age is evidenced by the large number of red stars that it contains. The cluster is about 11,000 light years from earth.
Finally, in the upper right part of the image is NGC 2423. This cluster is about 750 million years old, and lies about 2,500 light years away.
The image is a 2-panel mosaic. One panel comprises 19 X 180 sec. subs, the other 20 X 180 sec. subs, all shot at ISO 200. More gear and acquisition information may be found on the Astrobin page.
