Abstract: A dual beam optical spectrograph includes a housing defining an internal chamber that is divided into two subchambers with a partition. A liner array detector such as a charge coupled detector array (CCD) is located within the chamber symmetrically to either side of the partition. Two light inputs are provided to either side of the partition between the CCD and a planar diffraction grating, and each light input is led through a concave collimating mirror, a planar diffraction grating, and a concave focusing mirror before light impinges upon the CCD. The inventive spectrograph is capable of providing synoptic data since both optical channels are captured simultaneously. The housing can be mounted on an adapter for an IBM compatible printed circuit board.