From the National Optical Astronomical Observatories
The irregular star cluster M103, or NGC 581, is a distant cluster in the constellation Cassiopeia. One of the more remote open clusters, at about 8000 light years, M103's relatively small angular size still corresponds to a sizable 14 light year diameter (this image is only 8.6 arc minutes across). The bright binary (upper right, NW) is not part of the cluster. M103 may be over 20 million years old (there seems to be some dispute over its actual age). M103 is one of the 'extra' objects added from Mechain's observations but not actually observed by Messier. This true-color picture was created from fifteen images taken in the BVR passbands at the Kitt Peak National Observatory's 2.1-meter telescope, during the night of December 24th 2000
Image Title: The Irregular Star Cluster M103
Credit: Hillary Mathis, N.A.Sharp/AURA/NOAO/NSF
Text based on accompanying on-line materials.
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Last Modified On: Saturday, February 24, 2001