Discovery first recorded by Giovanni Battista Hodierna in 1654
M6 is known as the Butterfly Cluster. Robert Burnham discribed the cluster as a "charming group whose arrangement suggests the outline of a butterfly with open wings." The cluster is classified as an open star cluster in the southern constellation of Scorpius approximately 1,600 light-years from the Earth. The cluster is dominated by bright, blue, B-type stars, however; contrasting with its neighboring blue stars is the giant orange K/type BM Scorpii.
1https://en.wikipedia.org/wiki/Butterfly_Cluster
2http://www.messier.seds.org/m/m006.html