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 mum) spectrograph with several operating modes: high resolution, cross-dispersed with a resolving power of R = lambda/deltalambda approximate to 10,000, 0.5% spectral coverage, and a similar to1.5 x 8 slit; medium resolution, long-slit with R approximate to 15,000, 0.5% coverage, and a similar to1.5 x 45 slit; low-resolution, long-slit with deltalambda approximate to 0.004 mum, 0.25 mum coverage, and a similar to1.5 x 45 slit; and source acquisition imaging with 0.33 pixels and a 25 x 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.