A solar array positioning system includes first light sensor means facing the same direction as the solar array and second light sensor means facing the opposite direction. A third sensor, this one responsive to gravity, is employed to indicate the direction about a diurnal slew axis that the array is tilted. These sensors are employed to determine the initial array slewing direction to insure that during slewing and subsequent tracking, the array never is rotated through more than a given angle, less than 360.degree., between two fixed limits. This permits connection to the array by hard wiring rather than slip rings. The system includes also fourth sensor means for providing fine tracking signals which assume control of the array position during tracking. A vane structure reduces the sensitivity of various of the sensors to obscuration by foreign particles. A low cost uncorrected lens may be used with the fourth.