An optical system consisting of a convex reflective sphere or cylinder and a collimating lens is proposed to produce a collimated beam of solar radiation whose direction of propagation varies only slightly over the course of a day. Called a passive optical solar tracking (POST) system, a spherical version of the proposed device has limited usefulness for daylighting applications due to the inverse relationship which is shown to exist between collimated beam directional stability and contained flux. A cylindrical version of the system exhibits greater promise for solar illumination of building interiors. Other applications for the device are proposed for the fields of solar research, education, and artistic design.
© 1983 Optical Society of America
Ross McCluney, "Passive optical solar tracking system," Appl. Opt. 22, 3433-3439 (1983)