Combination of 15, 1 minute images unfiltered.
SBIG STL-1001E CCD. 20" f/6.8 Dall-Kirkham cassegrain telescope at prime focus.
NGC 2232 is a very large scattered cluster of stars surrounding the 5th magnitude star, 10 monocerotis. This star is a B-type main sequence star, located about 1300 light years from the Earth. There has been some debate about it being an actual member of the cluster, however Hipparcos data appears to confirm its membership. Most of the other bright stars in the cluster are also B-type main sequence stars. The cluster is so large that only the central regions are shown in the above image.