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Astronomy Image of the Day

NGC 869 & NGC 884: A Double Open Cluster

11 October 2005

Thomas V. Davis

NASA Astronomy Image of the Day for 11 October 2005

Most star clusters are singularly impressive. Open clusters NGC 869 and NGC 884, however, are doubly impressive. Also known as "h and chi Persei", this unusual double cluster, shown above, is bright enough to be seen from a dark location without even binoculars. Although their discovery surely predates written history, the Greek astronomer Hipparchus notably cataloged the "double cluster". The clusters are over 7,000 light years distant toward the constellation of Perseus, but are separated by only hundreds of light years.

Image and explanation courtesy of NASA Astronomy Picture of the Day