THE HIGH-RESOLUTION CROSS-DISPERSED ECHELLE WHITE-PUPIL SPECTROMETER OF THE MCDONALD OBSERVATORY 2.7-M TELESCOPE

A new high-resolution cross-dispersed echelle spectrometer has been in stalled at the coude focus of the McDonald Observatory 2.7-m telescope . Its primary goal was simultaneously to gather spectra over as much o f the spectral range 3400 Angstrom to 1 mu m as practical, at a resolu tion R=lambda/Delta lambda similar or equal to 60,000 with signal-to-n oise ratio of similar to 100 for stars down to magnitude 11, using 1-h exposures. In the instrument as built, two exposures are all that are needed to cover the full range. Featuring a white-pupil design, fused silica prism cross disperser, and folded Schmidt camera with a Tektro nix 2048X2048 CCD used at either of two foci, it has been in regularly scheduled operation since 1992 April. Design details and performance are described.