M48

 

Messier 48 is a conspicuous open cluster in Hydra,near its border to Monoceros. Spanning more than 50 minutes of arc in the sky, this cluster is almost twice the diameter of the moon although its core would actually fit inside that object. Under good seeing and dark skies, the cluster can be seen without optical aid but it is best appreciated with the use of a small binocular or short focal length telescope. About 50 stars can be seen that are brighter than 13th magnitude and another 30 are fainter than that. Lying at a distance of about 1500 light years, M48 is about 23 light years in diameter and is about 300 million years old. The hottest star is of spectral type A2 and mag 8.8; its luminosity is about 70 times that of the Sun. M48 also contains 3 yellow giants of spectral types G-K.

Image taken February 12, 2012 through broken clouds, with the D-90 and the 300 F:4.5 Nikkor piggy-back on the C-14. Exposure is 15 seconds at ISO 3200. Notice the satellite images - there was a 4th one in the upper left of the original frame that I cropped out.