To calculate precisely the APR is needed as input the cosine of the solar zenith angle. For this reason it should be specified lat, lon, yyyy, mm, dd, hh:mm. It should be also specified if it is desired the APR at surface or at the Top of the Atmosphere (TOA).
If you speak about atmospheric path radiance, you have to specify where are you looking (from TOA or BOA or in the atmosphere?). Furthermore, path radiance depends not only from the spectral domain but also on the geometrical configuration (i.e. illumination and viewing angles, zenith and azimuth) and the atmospheric (i.e. aerosol) and meteorological (i.e. water vapor) conditions.