An apparatus for testing an optical test piece comprising an interferometer for emitting an incident light beam. The apparatus includes a first reflective optic that receives the incident beam and produces a first reflected beam by focusing and expanding the received incident beam. The apparatus also includes a second reflective optic that receives and collimates the first reflected beam and outputs the collimated beam toward the optical test piece. Both the first and the second reflective optics are fixed to their respective positions relative to a thermally insensitive platform and the optical test piece is docked to the thermally insensitive platform and can be removed.