Abstract: A method and apparatus for active pyrometric measurement of the temperature of a body whose emissivity varies with wavelength. The emissivity is inferred from reflectivity measured at two wavelengths in an irradiation wavelength band and extrapolated to a wavelength in an emission wavelength band. The extrapolated emissivity is used to correct a blackbody estimate of the temperature of the body in the emission wavelength band. The extrapolation, being temperature-dependent, is done iteratively. Both reflectivity and emission measurements are performed via a common optical head that is shaped, and is positioned relative to the body, so that the optical head has a sufficiently large solid angle of acceptance that the measured temperature is independent of superficial roughness of the body.