Effective dust-temperature map for the Ophiuchus field. The cold structures are white, while the higher temperatures appear are dark. There are at least seven hot spots, all associated with massive ionizing stars in the region, implying a distance similar to the cloud material they are warming up. We note, by comparison with Figure 2, that most of the hot spots are associated with low column density regions, the ρ Oph shell being a particularly good example. The corresponding error map is presented in Figure B.2.