Open Cluster in Hydra 

Messier 48 is a large sprawling cluster that stretches across this entire image. It includes about 80 stars.

Charles Messier discovered this cluster in 1771. However, when later astronomers looked for it using the coordinates Messier provided, there was no open cluster to be found. For over 150 years, the identity of M48 was unknown. Finally, several 20th century astronomers concluded that Messier 48 is the open cluster NGC 2548, about 5 degrees north of the position Messier recorded. This is the only cluster in the area that fits Messier's description.

Magnitude 5.8
Apparent Size 30'
Distance (light yrs) 2,000
Right Ascension 8:13.8
Declination -5 45
Field of View 35' x 27'

Image details:  Exposure times of 12 minutes luminance and 9 minutes each of red, green and blue, taken with an SBIG ST-8300M imager and a 12" Meade telescope at f/5.6.

February 2012