A shadow band assembly includes a platform and an arcuate shadow arm extending upward from the platform and terminating in a free end above the platform. A sun sensor mounting location is located below the free end of the shadow arm. The arm is preferably further supported by a vertical strut. According to other embodiments, the arm is hollow and contains a fluid conduit and/or an electrical cable. A sun sensor may be mounted on top of the free end of the arm and a fluid nozzle may be mounted under the free end. A shadow band pyranometer includes the shadow band assembly, a sun sensor mounted at the mounting location and a motor drive coupled to the platform for azimuth tracking. Additional sensors with zenith tracking may also be provided.