Open Cluster and Planetary Nebula in Puppis
Star-hop chart
The portion of the Milky Way that passes through the constellation Puppis includes many open clusters, and one of the brightest, at magnitude 6.1, is Messier 46, which is about 5300 light yeas away. Its individual stars are not very bright, so the cluster appears as a dim circular glow through a typical pair of binoculars. Through a telescope, well over 100 stars can be seen in this rich cluster, and as a bonus, in the northern part of the cluster is the planetary nebula NGC 2438. This nebula is not actually a part of the cluster, and it is estimated to lie about 1000 light years further away. The nebula's blue-green color, circular shape, and dark center are clearly seen in this photo.
1.5 degrees to the west (well outside the field of this image) is another open cluster with a very different look, Messier 47.
| Magnitude | 6.1 |
| Apparent Size | 27' |
| Distance (light yrs) | 5,300 |
| Right Ascension | 7:41.8 |
| Declination | -14 49 |
| Field of View | 38' x 25' |
Image details: 10 exposures of 150 seconds at ISO 1600, taken with a Canon 400D camera through a Meade 12” telescope at f/5.4.
March 2010