Messier 6, the Butterfly Cluster   HOME INDEX BACK NEXT  

Open Cluster in Scorpius 

Messier 6 is a group of several hundred stars about 1600 light years away.  Many open clusters can resemble everyday objects if you use a little imagination, and looking through a telescope with a wide-field eyepiece it is pretty easy to see the butterfly pattern in Messier 6.  I have probably shown this cluster to hundreds of children at various public observing events, and when I ask them if they can find the butterfly pattern, most of them see it immediately.  Messier 6 is also a nice showpiece because it includes a variety of star colors.  Most of the stars are white or blue-white, but a few are yellow or orange.  In fact, the brightest star in the cluster, the variable star BM Scorpii on the edge of the butterfly’s left wing, has a distinct orange color.

Magnitude 4.2
Apparent Size 20'
Distance (light yrs) 1,600
Right Ascension 17:40.1
Declination -32 13
Field of View 29' x 22'

Image details:  Exposure times of 24 minutes luminance and 9 minutes each of red, green, and blue, taken with an SBIG ST-8300M imager and a 14" Meade LX850 telescope at f/6. 

September 2015