A solar energy harvester comprises: an elongated stationary solar irradiance converter assembly; a concentrator comprised of a substantially flat array of flat reflective heliostatic slats disposed at tilt angles to concentrate the sun onto the converter assembly, said slats each rotating in elevation about a north-south axis; sun sensor detecting the efficacy of concentration as the sun traverses; and control circuitry and drive motor positioning the collector in elevation according to the sun sensor so that the slat array tracks and faces the sun whenever the solar incident energy is greater than a selectable threshold level.