An exploded version of the prism cage in CorMASS: The three frames at the center-right side of the image form apetures which allow light to pass unobstructed through the prism. The cage is made of 6061-T6 Aluminum machined to a tolerance of .001". All other sides of the prism are covered by the cage for stray light reduction.
This view shows the collapsed view of the prism cage. Identified are the rotational and tip, tilt degrees of freedom. Rotation of the entire cage assembly is provided by a dowel pin on the optical bench. Tip-tilt is provided by shimming 3 orthogonal pads between the tip-tilt frames.
The prism is constrained through a system of six pads that form a semi-kinematic mount. Three spring plungers force the prism against the pads in all three dimentions.