M6 (NGC 6405) -- Open Cluster in Scorpius
“The Cloudy Ones Which Follow the Sting” – M6
Long before the Messier compiled his list of Deep Sky Objects and even before the
invention of the telescope, the Open Clusters of M6 and M7 were known as fuzzy
patches near the tail of the heavenly scorpion. The above quote is from Ulug Beg’s
Star Catalogue (1437). Today they are known as two of the largest and brightest of
the star clusters that can be seen in the night sky.
M6 and M7 are only about 3 ½ degrees apart in the night sky and together make a
stunning pair-of-clusters in binoculars. M6 has dimmer stars than M7, but then again
M6 is twice the distance of M7. Since M6 is also twice the size of M7 they both appear
to occupy the same amount of space (each about equal to the Full Moon) as seen from
earth. As the quote implies they are easily found following the sting (marked by the
stars Shaula & Lesuth) at the end of the Scorpion’s tail (Constellation Scorpius).
The arrangement of stars in M6 have given it the name of the Butterfly Cluster. In my
drawing the butterfly is flying head up at a 45-degree angle tilted to the left. The bright
orange star marks the edge of the right-Hindwing. If you don’t see a butterfly, that is
OK, since I am not 100% sure that I do.