A calibration system for a passive millimeter-wave (PMMW) camera. The calibration system includes a thermal calibrator having a first thermally conducting body, a second thermally conducting body, a first black body target mounted to a front surface of the first conducting body, a second black body target mounted to a front surface of the second conducting body, and a thermo-electric (TE) cooling device having a hot side and a cold side. The hot side of the TE cooling device is thermally attached to the first conducting body and the cold side of the TE cooling device is thermally attached to the second conducting body.