C76

NGC 6231 is a bright, compact open cluster in Scorpius, about 5,900 light-years away. At magnitude 2.6 it is visible to the naked eye, and it forms the core of the much larger Scorpius OB1 association. The cluster contains numerous hot O- and B-type stars.

Stunning in binoculars and small telescopes. Located just north of the Scorpion's tail near Zeta Scorpii. A telescope at 40-80x reveals dozens of bright blue-white stars. Best in summer evenings from locations with a good southern horizon.

Known since antiquity as a bright patch near the Scorpion's stinger. Giovanni Battista Hodierna first resolved it as a cluster before 1654. Sometimes called the Northern Jewel Box for its brightness and rich star field.