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cross dispersion spectrograph

(echelle spectrograph with additional disperser crosswise to the first)

A cross dispersion spectrograph uses two stages to increase its spectral resolution: first, an echelle grating, which separates the spectrum but with some overlap, and then crosswise to it (close to 90 degrees, I believe) an additional disperser, which could be a prism or a series of prisms. The result is a set of nearly parallel "bars" showing the light and dark portions of the spectrum, each bar showing a part of the spectrum, with some overlap with the adjacent bars. The rectangle encompassing these can be recorded with film or a CCD. Examples:

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