Diffuse nebula and open cluster in Monoceros
This is a very large but dim emission nebula that surrounds an open cluster of young, blue-white stars. The cluster is NGC 2244 (also known as Caldwell 50 or the Rosette Cluster), and at magnitude 4.8 it is bright enough to be seen with binoculars or even the naked eye.
The Rosette Nebula, however, has a low surface brightness, and although it is very large it is difficult to see except from a dark location. Because its diameter is about twice that of the full moon, an eyepiece with a wide field of view is needed to see it. On a dark clear night, try spotting this diffuse glow around the open cluster with a pair of binoculars.
| Magnitude | 5.5 |
| Apparent Size | 80' x 60' |
| Distance (light yrs) | 5,500 |
| Right Ascension | 06:33.0 |
| Declination | +4 57 |
Image details: Exposure times of 18 minutes each of lunimance, red, green, and blue, taken with an SBIG STF-8300M imager and a Tokina 500-mm lens at f/8.
January 2021