TEXES: A Sensitive High-Resolution Grating Spectrograph for the Mid-Infrared

We discuss the design and performance of TEXES, the Texas Echelon Cross Echelle Spectrograph. TEXES is a mid-infrared (5-25 μm) spectrograph with several operating modes: high resolution, cross-dispersed with a resolving power of R=λ/δλ~100,000, 0.5% spectral coverage, and a ~1.5"×8^'' slit; medium resolution, long-slit with R~15,000, 0.5% coverage, and a ~1.5"×45^'' slit; low-resolution, long-slit with δλ~0.004 μm, 0.25 μm coverage, and a ~1.5"×45^'' slit; and source acquisition imaging with 0.33" pixels and a 25^''×25^'' field of view on a 3 m telescope. TEXES has been used at the McDonald Observatory 2.7 m and the NASA Infrared Telescope Facility 3 m telescopes and has proved to be both sensitive and versatile.