The Dark Tower in Scorpius . ... Credit Copyright: Don Goldman Explanation: In silhouette against a crowded star field toward the constellation Scorpius , this dusty cosmic cloud evokes for some the image of an ominous dark tower . ... Known as a cometary globule , the swept-back cloud, extending from the lower right to the head (top of the tower) left and above center, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231 , off the upper edge of the scene. ...