An in-line night-day boresight with an adjustable wedge-prism assembly is
disclosed. The adjustable wedge-prism assembly includes two opposing
wedge prisms that are axially rotatable relative to each other. The
assembly is arranged in the optical path between the night optics and the
day optics. The adjustable wedge-prism assembly allows for compensation
of image shift errors introduced by the night optics due to manufacturing
errors in the night optics. This in turn allows for a cost-effective and
easily aligned in-line night-day boresight.