A correlation between spectral class and spectral irradiance using Planck's blackbody radiation

Stars may be used as calibration sources for sensors. This may be accomplished by a method that approximates the spectral irradiance of a star. This method distributes the total irradiance of a star as a blackbody function with an effective temperature. The results were compared with measured data. The accuracy of the method varied with the spectral class and luminosity type of a star. It also varied with the spectral range being considered. It was concluded that this method was a good first order approximation to the spectral irradiance of a star in the visual and infrared spectral regions but not in the ultraviolet spectral region.