Abstract: A solar energy collector including a solar energy receiver defining a primary target; and a field of heliostats mounted for angular adjustment to receive and direct sunlight to the primary target and an actuator to effect the angular adjustment of each heliostat. A secondary target at or spaced from the primary target. A controller coupled to the actuator configured to sequentially cause, a temporary angular adjustment of the respective the heliostats so as to divert the beam of sunlight received at each heliostat to the secondary target for a predetermined period of time. A recorder to record a representation of each diverted beam at the secondary target. The controller is coupled to the recorder and further configured to respond to the representation of the diverted beam for the respective heliostats when a parameter deviates from norm, by activating the actuator to angularly adjust the corresponding heliostat.