Abstract: The present invention selectively corrects astigmatism and is simple and inexpensive to implement. A spherical mirror is bent to simultaneously increase radius of curvature in one plane and decrease radius of curvature in the plane at right angles thereto. In one implementation the mirror disposed in a mounting that includes a plurality of abutment surfaces against which a front surface of the spherical mirror abuts to effect bending of the mirror when it is appropriately disposed in the mounting. The plurality of abutment surfaces includes at least two bending surfaces and at least two support surfaces. The bending surfaces are higher than the support surfaces, relative to a surface of the mounting from which they extend.