Abstract: Disclosed is a mechanical translation linkage and lamp support apparatus for maintaining the projection light source inside a gimballed transparency displaced from the geometric center of the transparency and in a fixed spatial relation with the center of the transparency as the transparency rotates about any of its three mutually perpendicular axes. The translation apparatus employs only a mechanical linkage to ground and reacts to rotation of the support gimbal about either the X or Y axis to maintain the projection light source at the required position regardless of the attitude of the gimbal.