FEROS, the Fiber-fed Extended Range Optical Spectrograph for the ESO 1.52-m Telescope

FEROS is a fiber-fed bench-mounted prism-crossdispersed echelle spectrograph for the ESO 1.52-m telescope at La Silla. It works in quasi Littrow mode and in white pupil configuration. For the object and the nearby sky, the complete optical spectrum from 370–860 nm is recorded in one exposure with a resolving power of R = 48,000 by the use of a two-beam, two-slice image slicer. A first concept of FEROS, which is supposed to replace ECHELEC at the 1.52-m telescope, was presented by Pasquini et al., 1992, “FEROS for the ESO 1.52-m Telescope”, 32nd Scientific Technical Committee Meeting, Garching. Designed as a fiber-linked spectrograph connected to the permanently mounted Boller & Chivens spectrograph it has the advantage of being always available. The fibre entrance of FEROS is mounted on the slit unit of the Boller & Chivens spectrograph, and it will be possible to change from one spectrograph to the other by a simple translation of the slit unit. Because FEROS provides highdispersion spectroscopy with a wide, simultaneous wavelength coverage, this instrument mounted on an intermediatesize telescope fills a gap in the present and future ESO instrumentation park. It will allow to realise many important scientific programmes (a few of which are described below) of objects down to about 16th magnitude with high efficiency, little constraints on operations and will relieve the pressure on larger telescopes. FEROS is built for ESO by a consortium of four astronomical institutes under the leadership of the Landessternwarte Heidelberg (LSW). The Principal Investigator (PI) of the FEROS project is Prof. Dr. Bernhard Wolf at the LSW. Further members of the consortium are the Astronomical Observatory Copenhagen (AOC), the Institut d’Astrophysique de Paris (IAP), and the Observatoire de Paris/Meudon (OPM). The contract between ESO and the FEROS Consortium was signed in September 1996. It is planned that the instrument will be available to the community in early 1999. Scientific Objectives