M6, NGC 6405; Butterfly Cluster

The open star cluster M6, or NGC6405, is also known as the Butterfly Cluster. M6 is visible to the naked eye in the constellation Scorpius. The visually most conspicuous star is rather reddish and is actually a slow, semiregular variable. M6 is variously estimated as between 50 and 100 million years old. The images were taken in June 1995 at the Burrell Schmidt telescope of Case Western Reserve University's Warner and Swasey Observatory, during the Research Experiences for Undergraduates (REU) program operated at the Kitt Peak National Observatory and supported by the National Science Foundation.