Multiwavelength RGB images (colored as indicated in the upper left corner of each image) of the Berkeley 87/ON2 region, and infrared color–color diagram of the OMEGA2000 field. The extinction vector that is shown in this diagram (panel b) is obtained from Indebetouw et al. (2005), and taking A_K/A_KS ≈ 0.98 (which is justified in Appendix A). In all the images, the Cl05 region is enclosed by a white or black circle. In the Herschel RGB image (d), the OMEGA2000 field coverage is shown as a white square. An infrared closeup of this field, centered on [DB2001] Cl05, is displayed in panel a, and its Chandra counterpart is shown in panel c. The latter is made of 2-pixel binned images from the 2009 observation; the density of J − H > 1.7 sources is drawn as gray contours (dotted = 55 arcmin⁻²; dashed = 110 arcmin⁻²). In all panels, Berkeley 87 spectroscopic members are marked as open blue diamonds, except for WR 142, which is shown as an open blue circle (only in panels b and d); crosses are point sources within the Cl05 region that are simultaneously detected in J, H, K, and [5.8] (i.e., those that are represented in panel b).