Patent ID: 8294988

Claim:
An optical system comprising: a first lens group comprising a plurality of lenses, the first lens group being configured to correct for lateral chromatic aberration; and a second lens group comprising a plurality of lenses, the second lens group being configured to correct for axial chromatic aberration, the second lens group being disposed adjacent the first lens group, a detector disposed behind the second lens group; a mechanism for switching a configuration of the optical system between a narrow field of view (NFOV) configuration and a wide field of view (WFOV) configuration; a ray path steering system disposed in front of the first lens group, the ray path steering system comprising a pair of counter-rotating grisms configured to enhance a field of regard of the optical system; and a stabilization system configured to suppress image jitter, the stabilization system including a mechanism for decentering at least one lens in the first lens group or in the second lens group orthogonal to an optical axis of the optical system; wherein a pupil of the optical system is located external to the first lens group and second lens group for placement of a cold shield within a cryo-vac Dewar enclosing the detector; and wherein the second lens group comprises a first lens element having a positive power, a second lens element having a negative power, a third lens element having a positive power, a fourth lens element having a negative power, and fifth and sixth lens elements having substantially zero power.