PSC near‐IR color‐color diagram for targets in the 90547 calibration field. This is a ﹩\left|b\right|< 20^{\circ }﹩ field, so all targets are brighter than 14.3 at K_s and lie within the two‐box color cut. Data are shown in black, with typical PSC error bars shown in green. This figure, along with Fig. 5, illustrates the large uncertainty in the PSC colors relative to the Cal‐PSWDB colors, and the relative difficulty in removing background contaminants from ﹩\left|b\right|< 20^{\circ }﹩ fields. An ﹩A_{v}=1﹩ interstellar reddening vector is shown in red.