Wedge prisms are used as beamsteering elements in optical system. By combining two wedges of equal power in near contact, and independently rotating them, a ray can be steered in any direction within the narrow cone. The equation to determine the deviation angle is: θd = arcsin(nsinθw)- θw Where θd is the deviation angle, θw is the wedge angle, and n is the nominal index at the appropriate wavelength..