Abstract: An optical element (10) is mounted and aligned with minimum strain and distortion within a housing (12) to which at least three mounts (14) are attached and spaced about 120.degree. apart the periphery of the optical element. Each mount comprises a spherical disc (16) housed within an annular ring or sleeve (18), and each disc abuts and supports the optical element. Any loading exerted on the housing causes the discs to slide and/or rotate with respect to the annular disc-retaining sleeves to prevent such loadings from being transmitted to the optical element, thereby enabling the optical element to maintain a chosen, strain-free orientation.