Shading by clouds can affect the amount of flux on a heliostat which in turn can affect the energy generated by the solar device. Real-time monitoring of cloud shading of at least a portion of the solar field can allow for more efficient operation of the entire solar power system. For example, diffuse solar radiation and global horizontal radiation may be measured in certain parts of the field in order to estimate the direct normal radiation at any point in the solar field. A cloud map generated based on an image taken of the cloud may be used in calculating the direct normal radiation. By knowing the amount of direct normal radiation at any point in the solar field, the solar energy system can be changed or maintained. For example, the operating parameter may include aiming directions for one or more of the heliostats.