The Resonance Ltd vacuum monochromator and spectrometer packs great performance in a small package. The system can be coupled directly to a vacuum chamber through a 2.75" Conflat® style flange to observe processes in a vacuum system. The standard VUV grating has high dispersion and exhibits high efficiency in the VUV and UV regions. Cost effective interchangeable gratings can be used to extend the range in the visible and IR regions. The system can be operated with a gas purge or evacuated allowing spectra to be obtained in the VUV as well as regions in the IR where atmospheric absorption is high.