Spectrograph

A spectrograph is an optical instrument that light of different wavelengths into its spectrum decomposed (ie, in its various colors) and registers the spectrum generated by means of suitable detectors. The decomposition of the light according to its wavelength, is done with the aid of optical elements having dispersion properties, generally either a prism, a diffraction grating or a grism so-called, the grating and the prism are combined in one element.

Spectrographs are used among other things as observation unit of astronomy that disperses the light emerging from a telescope light from stars or galaxies in its spectrum and leads to a detector.

Such detectors were formerly mostly photographic plates and films. Today, especially CCD elements or photodiode arrays are used for the purpose of detection of the spectrum generated by the spectrograph.

Instruments for visual observation of spectra called spectroscopes.