Designation: M6 / NGC 6405
Distance: 1,600 light years
Object type: Open cluster
The Butterfly Cluster is a bright open cluster lying some 1,600 light years from us, in the southern constellation Scorpius. The cluster has an estimated age of around 100,000 million years, and spans some 12 light years across. It contains over 300 stars, most of which are hot, blue stars although the brightest star is an orange giant belonging to the spectral class K.
The Butterfly Cluster was discovered by the Italian astronomer Giovanni Battista Hodierna in 1654, although previous observations may date as back as the 2nd century. It was only in 1764 that Charles Messier entered the cluster in his catalogue, as object number 6.
Total integration time: 8 hours 40 minutes
Acquisition software: CHI-1 (Telescope Live)
Processing software: PixInsight