Apparatus for detecting multiple spectral bands, individually or concurrently, using linear detector arrays (30, 36). The system employs a beamsplitter (12) to divide the optical source (10) into two or more optical beams (24, 32), which beams are directed at the linear detector arrays (30, 36). Filter trays (38, 40) are positioned in the focal planes of the optical beams (24, 32) so that the beams pass through the filter trays prior to impinging upon the detector arrays (30, 36). Multiple filters (42, 44, 46, 48, 50, 52) are placed on the filter trays (38, 40). Linear actuators (62, 64) positioned adjacent the filter trays (38, 40) translate the trays across the focal planes of the optical beams (24, 32) so that individual filters are positioned in the path of beams, such that those frequencies of the beams that fall within the spectral ranges of the individual bandpass filter through which it passes may be detected by the detector arrays for further examination and analysis.