Digital Sky Survey (DSS2, red band) image of the northern part of Sco OB1. The image size is 2.6° × 2.6° and coordinates are J2000. The FOVs of existing X-ray images are indicated with red squares (Chandra) and a circle (XMM-Newton). The massive cluster NGC 6231 is well visible inside the two southern Chandra fields. The northern Chandra field is centered on the IR source IRAS 16562-3959. Near the middle, the larger XMM-Newton FOV is centered on the Wolf-Rayet star WR79a, in the Tr 24 region. The bright nebula near top center is IC4628.