NOVELTY - The system (102) has a sky imager (114) which is provided with a customized lens (116). The customized lens is configured to capture planar images of sky. An image processor (118) is coupled to the sky imager and is configured to process the planar images. A computing system (119) is coupled to the image processor. The image processor is configured to detect the cloud characteristics based on the planar images, and predict the solar irradiance based on the cloud characteristics.    USE - Prediction system for predicting solar irradiance of solar plant based cloud characteristics. Can also be used in meteorological centers to determine weather change.    ADVANTAGE - Since the image processor is configured to detect the cloud characteristics based on the planar images, and predicts the solar irradiance based on the cloud characteristics, the cloud movement can be easily discerned and the faster computation of cloud characteristics can be achieved. The actual size and the actual movement of the cloud can be accurately depicted by the customized lens. The rate of change of the image point on the image sensor can be effectively improved. The saturation and/or distortion of the captured images can be effectively prevented by the sky imager. The steady state condition can be achieved by the auxiliary power source. Hence the efficiency of the prediction system can be increased and faster prediction of irradiance can be allowed for the solar plant to implement plant control with minimum delays.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a sky imager for the prediction system;    (2) a method for predicting power output of solar panels in a solar plant based on cloud characteristics; and    (3) a non-transitory computer-readable medium storing programs for predicting power output of solar panels in a solar plant based on cloud characteristics.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram illustrating the prediction system for solar plant.    Prediction system (102)    Sky imager (114)    Customized lens (116)    Image processor (118)    Computing system (119)