M 6

Butterfly Cluster in Scorpius

A "charming group whose arrangement suggests the outline of a butterfly with open wings." (Burnham). The diameter of this star cluster is some 20 light years, with an estimated average density of 0.6 star per cubic parsec. Its age was estimated to 100 million years according to Burnham, and to 51 million years according to the Sky Catalog 2000. The brightest star in this cluster is a yellow or orange giant of apparent magnitude 6.17, while the hottest stars are blue main sequence stars of spectral type B4-B5.

Of all Messier objects, M6 is apparently situated closest to Galactic Center, which is located in the constellation Sagittarius but very near to the 3-constellation edge of Sagittarius, Scorpius and Ophiuchus.

Right ascension	17 : 36.8 (hours : minutes)
Declination	-32 : 11 (degrees : minutes)
Distance	2.0 (light-years*10^3)
Visual magnitude	5.3