spectra of acetylene-oxygen detonation were studied in the wavelength range 3000-6000 A. Special interest was given to the continuums. It was found that the detonation products, in the case of stoichiometric and lean mixtures, radiate in black body manner, to a good approximation, in the wavelength range 5150-5650 A. This phenomenon was used to calculate the temperature of the detonation products. The temperature calculated using measured pressure and heat transfer, together with one dimensional detonation theory and the necessary thermodynamic data, is in the average about 300 K higher than the experimentally observed temperature. This difference is in the same direction as reported by H. Miyama 21, G.B. Kistiakowsky 20 and M. Veyssiere 9. It is also to be expected that the calculated temperatures will be lower than those calculated here, if the flow field is calculated using the appropriate non-steady calculations over the entire flow field beginning at the ignition point.