Optical system with variable dispersion

An optical system capable of variably dispersing incident electromagnetic energy, comprising at least two optical elements spaced apart a fixed distance, whereby rotation of one or more of the optical elements relative to one or more of the other optical elements changes the degree of dispersion, and rotation of all of the optical elements together in a common direction changes the orientation of the dispersion, a detector at a fixed distance from the optical elements to receive electromagnetic energy from the optical elements and convert it into electronic data, a controller that controls the rotation of the optical elements to selectively vary the dispersion of the electromagnetic energy and the orientation of the dispersion produced by the optical elements on the detector and a processor that analyzes the electronic data to identify spectral signatures of objects in the system's field of view.