A wide field-of-view optical system that may be used in determining a direction to a source of light, or for determine steering corrections to direct a vehicle toward a target, is disclosed. The optical system, which may be used as a seeker in a missile or other weapon, comprises a spherical ball lens truncated to provide one or more facets on which detectors may be mounted to measure relative intensities as a blur spot image of a source of light, which may be a reflection from a laser designated target, moves across the detectors, which may be individual elements in a quadrant detector. Narrow band filters may be used to suppress undesired wavelengths and enhance performance. The innovative design enables implementation of a wide field-of-view seeker with no moving parts. The spherical ball lens may be used directly as an aerodynamic surface without a need for a separate optical dome.