A specialized collimator used to calibrate infrared/night vision fire control systems. The collimator contains a reticle which can be seen by the thermal sensor of the device being calibrated. The design allows aligning in lighted or unlighted conditions. Variations can be provided. The Warren-Knight 29-0741 Thermal Collimator has a length of 36″ and a height of 12.12″ with a 10.5″ width. It weighs approximately 40 lbs.