NGC 7789 in Cassiopeia is one of the richest galactic star clusters in the sky. It consists of over 1000 stars of magnitude 10.7 and fainter in an area half the size of the full moon. This cluster was first discovered by Caroline Herschel (William's sister and assistant) near the end of the 1700s.
Cassiopeia, zoom lens photograph.
NGC 7789, Newtonian photograph.
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