A warning receiver includes an anamorphic lens positioned to receive light within a field-of-view (FOV) defined by first and second angles that are orthogonal to each other and compress the light along the first orthogonal angle into a single line along the second orthogonal angle. A dispersive element is positioned to separate the single line of light into a plurality of wavelengths to produce a two-dimensional light field indexed by the second orthogonal angle and wavelength. A pixelated detector is positioned to receive the light field and readout electrical signals indexed by the second orthogonal angle and wavelength. A processor coupled to the pixelated detector process the electrical signals to detect and characterize an optical source within the FOV.