Optical Surfaces Ltd. has launched a series of motorized optical mounts designed for positioning large precision optics, such as off-axis paraboloids and spherical or flat mirrors in applications where pointing stability is important. The devices provide resolution of up to 0.1 arc sec and unidirectional repeatability of 0.5 arc sec. Four standard models cover apertures from 305 to 550 mm. The 305-mm version offers ±7° rotation in the elevation and azimuth axes. The devices are robustly designed for reliable operation even with heavier loads. They come with a stepper motor or, for highest resolution positioning, with a DC brush servomotor. Remote control via PC software enables use in hostile environments, within a vacuum or where limited space makes manual adjustment difficult.