Abstract: A disk segment is used to facilitate mounting a mirror to a limited rotation motor. The disk segment has a flat edge which defines a cutaway portion such that, when the flat edge is aligned with the plane defined by the reflective surface of the mirror, the disk segment does not impede access to the reflective surface for polishing and other operations. The disk segment is attached to the mirror before the mirror is finished, thereby enabling use of attachment techniques that would be damaging to a finished mirror. The disk segment may be secured to the motor shaft by various means, including but not limited to a threaded coupling and clamp ring. The coupling may include a tapered shaft or compression fitting in order to facilitate rotational alignment of the mirror relative to the motor. Alternatively, the disk segment may be secured directly to a threaded motor shaft with the clamp ring.