Contributed paper on
ESPaDOnS: An Echelle SpectroPolarimetric Device for the Observation of Stars at CFHT

J.-F. Donati, C. Catala and J.D. Landstreet

presented at the ``fifth CFHT users' meeting'', eds: P. Martin and S. Rucinski (1998)

50 kbyte .ps.gz file or html document

We present below an ongoing project for a new bright time instrument, a cross-dispersed échelle spectrograph/spectropolarimeter called ESPaDOnS, for general community use at the Canada-France-Hawaii Telescope (CFHT). The design specifications for this instrument are that it is to be able to obtain a complete optical spectrum (i.e. from 370 to 900 nm) in a single exposure, with a resolving power of about 50,000. If desired, ESPaDOnS will be able to measure all the polarisation components of the stellar light (circular and linear) with the same resolving power. The spectrograph will be bench-mounted and fed by a double optical fibre from a Cassegrain module containing all calibration facilities and the optional polarisation analyser, making it possible to have extremely good wavelength stability and minimal instrumental polarisation.
ESPaDOnS should be a unique instrument worldwide in polarimetric mode, competitive with similar instruments on 8 m class telescopes in non-polarimetric mode. With this facility, French and Canadian astronomers should be able to address with unprecedented detail a broad range of important issues in stellar physics, from studies of stellar interiors, to investigations of stellar atmospheres, stellar surfaces, stellar magnetic fields, and to observations of circumstellar environments and extrasolar planets.