Instrument on the ESO 3.6-metre telescope

This is CASPEC, the Cassegrain Echelle Spectrograph, based on the Cassegrain focus of the ESO 3.6-metre telescope at La Silla Observatory, in Chile. CASPEC has now been decommissioned, but in the past it was able to obtain high-resolution spectroscopic observations of stars, nuclei of galaxies and quasi-stellar objects (QSOs) as faint as magnitude 16 with its signal-to-noise ratio, that were only then possible to obtain with large coudé instruments. This gave ESO astronomers the possibility to carry out detailed observations of the physical conditions and abundances of faint stars and extragalactic observations at this spectral resolution for the first time.