M103

From South Dublin Astronomical Society

M103
Type	Open cluster
NGC	NGC 581
Constellation	Cassiopeia
Right Ascension	1h 33.2m
Declination	+60° 42'
Magnitude	7
Size	6 arc min.
Image:M103 messier image.jpg

It sometimes seems that wherever you point your binoculars in Cassiopeia you are sure to find an open cluster. The constellation is chock full of these stellar aggregations to delight the binocular observer. A degree northeast of Delta Cassiopeiae (Ruchbah) is the small open cluster M103, appearing as a fan-shaped glow in smaller binoculars but resolved into a number of pinpoints of light in larger instruments. Just 1½º further to the northwest is NGC 663, a broader group where some of the brighter suns are easily seen. A detailed star chart will help you identify some other NGC clusters that are in the area too. M 103 is relatively remote at 8,500 light years and is estimated to be about 25 million years old. Over 150 stars are considered members of the group. NGC 663 is a little closer at 6,300 light years.