Optical Surfaces Ltd is a leading manufacturer of high precision hyperbolic mirrors that are used in satellite-based telescopes to collect and focus light enabling high-resolution remote observation in applications including agriculture, water resources, urban planning, rural development, mineral prospecting, environment, forestry and disaster management.
Hyperbolic secondary mirror (courtesy: Optical Surfaces Ltd.)
Earth observation satellites employ hyperbolic mirrors in their telescope design to allow high optical performance over a large field-of-view in a compact footprint. A hyperbolic secondary mirror is used in Cassegrain telescopes to effectively balance aberrations caused by the shorter focal length of a typically parabolic primary mirror. In addition, in some more extreme low f/ratio applications served by Ritchey-Chretien telescopes, both the primary and secondary mirrors may be hyperbolic.
Drawing upon a uniquely stable production environment - Optical Surfaces skilled optical engineers are able to produce secondary convex hyperbolic mirrors up to 150 mm diameter with typical wavefront error of only lambda/20 P-V, surface finish of 10/5 and microroughness of less than 1.2 nm RMS. Such customer specified ultra-smooth hyperbolic mirrors can be supplied with a coating exactly optimised for your application. In space borne telescope platforms, where weight is an issue, Optical Surfaces can also produce hyperbolic mirrors with light-weighting options.
Source: https://www.optisurf.com/