There is significant interest within the combustion community in thermite reactions with nanoscale particles due to their high flame temperatures and fast combustion velocities. However, the mechanism by which the reaction propagates is not well understood. The reaction temperature, the heating rate, and the reaction zone thickness are critical parameters to understanding the mechanism. Measurements of the reaction temperature for the Al/CuO system are made using multi-wavelength pyrometry for two different configurations. In one experiment, the radiative emission from the reaction of a small, unconfined pile (∼10mg) of the Al/CuO nanothermite is collected over a 50 ms integration time and the average temperature is measured. In the other experiment, the radiative emissions are collected from a single spot on an instrumented burn tube filled with the nano-thermite as the combustion wave passes and temporal change of temperature is measured.