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Spectral emissivity is considered as one of the most critical thermophysical properties influencing photothermal conversion efficiency of solar selective absorbers. In addition, long-term stability at high temperature and thermal shock resistance are the performance-limiting properties of spectrally selective absorbers. In this context, this study reports the variation of emissivity with a change in emergence angles and operational temperatures for the newly developed W/WAlN/WAlON/Al₂O₃ absorber. An analysis of the experimental results demonstrates that hemispherical emissivity values at elevated temperature are comparable while calculated using both room temperature and high temperature reflectance data. Hence, the applicability of the room temperature measurement method is validated to evaluate high temperature emissivity. The analysis of angular measurements indicates an insignificant difference …