Abstract
A geometrical analysis of image formation in single monochromators is expanded to include the dual monochromator and the tandem monochromator, a system of two single monochromators used in series. The tandem system is useful in measurements of monochromator transmittance and in providing double dispersion. This analysis leads to expressions for the passbands, radiance in the final slit plane, and transmitted flux, as the widths of the intermediate and final slits are varied. © 1963 Optical Society of America.