The high-resolution cross-dispersed echelle white-pupil spectrometer of the McDonald Observatory 2.7-m telescope

TLDR

The paper presents the design details and performance of the spectrometer. The instrument employs a white‑pupil design with a fused‑silica prism Ross disperser and a folded Schmidt camera feeding a 2048 × 2048 Tektronix CCD, and has been in regular use since April 1992. A high‑resolution cross‑dispersed echelle spectrometer covering 3400 Å–1 µm at R≈60 000 and S/N≈100 for stars down to magnitude 11 has been installed at the McDonald Observatory 2.7‑m telescope, requiring only two 1‑hour exposures to cover the full range.

Abstract

A new high-resolution cross-dispersed echelle spectrometer has been installed at the coude focus of the McDonald Observatory 2.7-m telescope. Its primary goal was to simultaneously gather spectra over as much of the spectral range 3400A to 1 micron as practical, at a resolution R = lambda/delta-lambda ≃ 60,000 with signal-to-noise ratio of ~100 for stars down to magnitude 11, using 1-hour 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 ross disperser, and folded Schmidt camera with a Tektronix 2048 X 2048 CCD used at either of two foci, it has been in regularly-scheduled operation since April 1992. Design details and performance will be described.