The Short Wavelength Spectrometer (SWS) onboard ESA's InfraRed Space
Observatory (ISO) provided medium and high spectral resolution in the
wavelength region 2.38-45.2
.
Its two nearly independent grating
spectrometers had a spectral resolution of 
1,000-2,000, corresponding to a velocity
resolution of
300-150
km s-1. By inserting Fabry-Pérot (FP) filters, one for the range
15-26
(with capability down to 11.4
at reduced
resolution) and the other for the region
26-35
(with capability to 44.5
at reduced sensitivity),
the resolution could be increased to
,
10 km s-1.
The SWS wavelength range is of great scientific interest, not only because it is here that cool objects in the temperature range 1500-80 K radiate the bulk of their energy, but also because of its rich variety of atomic, ionic, molecular and solid-state spectral features. These provide unique and excellent tools for studies of the physical and chemical processes in the universe, especially of those regions optically hidden by interstellar dust. The SWS spectral resolution allows probing of kinematic processes in a variety of objects ranging from nuclei of galaxies to planetary atmospheres.