The open star cluster in this image, NGC 6231, is located at the south-western bend of the Scorpion's tail in the constellation of Scorpius. This young cluster, only about 6.5 million years old, is approaching us at the speed of 100 000 kilometres per hour. Its hottest star, Zeta1 Scorpii, ranks as one of the most massive stars in the Milky Way galaxy. It belongs to the Scorpius OB association of very young and hot stars.

At the upper left side, a cometary globule known as "Dark Tower" is shaped by intense ultarviolet radiation from NGC 6231.

IC 4628 nebula is also visible at the top right of this wide field image.