NGC 6231 is one of the prettiest premium open clusters in the sky. It shines at magnitude 2.6 and spans an area half that of the moon.

It's easy to mistake it for a comet. You can imagine the stars Zeta 1 Scorpii and Zeta 2 Scorpii forming the comet's nucleus and NGC 6231, Collinder 316, and Trumpler 24 to the north forming the tail.

This very young open cluster (about three million years old) contains lots of young hot giants and supergiants. It also contains two extremely rare Wolf-Rayet stars, which are very hot, massive stars rapidly bubbling off their bulk and converting it to super-hurricane-force stellar winds.

Click here to see if this object is visible in your sky tonight.