A through-optical bench is the optical equivalent of a folded-optical system. Folded optics is generally found in cannon launched guided projectiles and always includes a mirror mounted on a gimbal. Inside the projectile the optical image is hidden behind the mirror and is not easily accessible by measurement instrument. In the through-optical bench the image is repositioned to where it is easily viewed; hence enabling a much finer process to improve manufacturing accuracy and throughput. The through-optical bench uses a collimated beam of light which passes through the seeker nose optical cluster, then through a mask which mimics the mirror, then through an identical optical cluster which substitutes for the reflection, and finally onto a screen to form a focused image directly viewable by a microscope. The clusters and mask simultaneously step through various yaw angles made possible by a reversing linkage that moves them as mirror images. A micrometer dial simulates the focusing shim for the particular seeker nose cluster.