In-orbit performance of the ISO long wavelength spectrometer

The long wavelength spectrometer on-board the European Space Agency IR Space Observatory (ISO) uses a grating and one of two Fabry-Perot interferometers to make medium (λ/Δλ ∼ 200) and high (λ/Δλ ∼ 10000) resolution spectroscopic observations in the 43-196.9 μm wavelength range. The instrument has been in continuous use since the launch of ISO in November 1995. In this paper we describe the calibration of the instrument and its performance, both spectroscopic and photometric, over the two years of instrument operations. ©2003 Copyright SPIE - The International Society for Optical Engineering.