Michelle: a versatile mid-infrared echelle spectrometer for the U.K. Infrared Telescope

We present the optical design for Michelle, the UK Infrared Telescope's next major spectrometer which is now under construction at the Royal Observatory Edinburgh. Operating in the 10 and 20 micrometers atmospheric windows, Michelle will be capable of taking spectra at resolving powers ranging from 40 to 20,000 over a region of sky an arcminute long and varying in width from 0.75 arcseconds upwards. This high degree of versatility reflects Michelle's role as the U.K. astronomy communities sole long-slit mid-infrared spectrometer and as a primary tool for following up on the discoveries of the ISO satellites.