The radius of curvature of a mirror determines its magnification factor and its focal length. Newton used a concave spherical mirror to make his reflecting telescope, a design that is still ...

The concave concrete structures were ... and a cataloguing of all the remaining examples." Joe Pettet-Smith "The design of the Selsey mirror in West Sussex matches structures on the Northern ...

The concave concrete structures were designed ... celebration and a cataloguing of all the remaining examples." "The design of the Selsey mirror in West Sussex matches structures on the Northern ...