High-resolution observations of cool stars with the ESO Coude' Echelle Spectrometer

Abstract

A new instrument capable of providing high spectral resolution observations of relatively bright objects became operational in 1982 at the European Southern Observatory (ESO) at La Silla (Chile). This is the Coud~ Echelle Spectrometer (CES), which in its present configuration is normally fed from the 1.4 m Coud~ Auxiliary Telescope (CAT). The optical configuration uses an echelle grating and a prism predisperser. The instrument can be operated either in a scanner or multi-channel mode. In the latter mode the detector used is an 1872 channel Retieon cooled to 140 K. The resolving power attainable in this mode is typically of the order of 105 . The system appears to have a very pure instrumental profile and low scattered light. Further details on the instrument can be found in Enard (1982).