Astrophysics (index)

Cross Dispersion Spectrograph

(echelle spectrograph with additional disperser crosswise to the first)

A Cross Dispersion Spectrograph uses two stages to increase its Spectral Resolution (R): 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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