A spectrograph that uses an echelle grating to achieve very high spectral resolution and wide wavelength coverage. The overlapping spectra produced by the grating must be separated before they reach the detector. The separation is usually done by a prism or a grism (sometimes called a cross-disperser), which places the sorted spectra one above the other. In combination with sensitive detectors such as CCDs, echelle spectrographs are becoming increasingly important in astronomy for high-resolution spectroscopy.
Subjects: Astronomy and Astrophysics.