The advantage of trough collectors is to require tracking the sun only in one direction, because in the other direction they do not perform sun concentration. The solar trough axis can either be placed parallel to the North-South direction or parallel to the East-West direction. In North-South positioning the tracking system follows the sun in its daily excursion. In East-West placement the tracking system follows the displacements in sun’s altitude occurring every day of the year. For the studies presented in this paper the North-South positioning is preferred to the East-West placement. The paper examines the effects of an incorrect placement of collector axis, proposing an empirical correction procedure to recover the lost energy. Considering North-South positioning with errors up to 15° of misalignment, the study evidences that they cause significant losses of collected energy. Moreover the amount of missing energy always depends on sun’s altitude. Using the tracking system to compensate misalignment errors it is possible to recuperate most of the lost energy. This recovering procedure is applied to a trough concentrator with parabolic profile. Keywords: sun tracking, simulations.