M103 (NGC 581)
Messier M103 (NGC 581) is a open cluster located in the constellation Cassiopeia, in the Perseus Arm of the Milky Way Galaxy. in the Local Group of galaxies.
Messier M103 is best viewed during winter, is magnitude 7.0*, and can be viewed with binoculars. It is 6' in size. For reference, the full moon is 30' (arc minutes) in size.
* The naked eye can see up to magnitude 8 objects under ideal dark sky conditions.
Find your inner astronomer. Your complete guide to amateur astronomy.