M6 - Open Star Cluster in Scorpius

M 6 is commonly known as the Butterfly Cluster. The astronomer Giovanni Battista Hodierma is allegedly the first person to record this object. However, Robert Burnam suggested that Ptolemy may have observed it while recording M 7 (the cluster that bears his name). Charles Messier added this to his catalogue in 1764.

M 6 lies 1600 light years away and spans 12 light years. It contains approximately 80 stars. Most of its stars are hot blue (B-type) although the brightest star in the cluster is a K-type orange giant.

Taken from my residence in southeastern Minnesota on 8/5/16.


Telescope: Sky-Watcher 120ED
Mount: Sirius EQ-G
Camera: Modified Canon 650D; raw capture; ISO 800
Exposures:  24 @ 3 min.
Note: Camera was focused using a Bahtinov mask and live view. The subframes were aligned and combined in ImagesPlus. The composite image was adjusted in Photoshop. Topaz DeNoise was applied to reduce grain.
Back to Index