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A spectroscope fitted with a camera or an electronic detector such as a charge-coupled device (CCD) used to obtain a permanent record of the spectrum so that the intensity at different wavelengths can be measured. It consists of a slit for isolating the light from a particular object in the telescope’s field of view, a collimator for directing this light into a parallel beam, a diffraction grating or prism for creating the spectrum, and a detector for recording the spectrum. In the past the detector would have been a photographic plate but today CCDs, which are far more sensitive, are typically used instead.

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