THE PHOTOMETRIC CALIBRATION OF THE ISO SHORT-WAVELENGTH SPECTROMETER

We give an overview of the photometric calibration of the Short Wavele ngth Spectrometer (SWS) through the Performance Verification phase. Th e basic strategy for deriving absolute flux densities from detector ou tput for the grating and Fabry-Perot sections of SWS is reviewed, and the results are demonstrated with 2.4 - 45 mu m spectra of representat ive standards gamma Dra, alpha Lyr, and gamma Cru. The effects of in-o rbit changes in the relative spectral response function (RSRF) and ISO pointing are discussed. The systematic continuum flux level uncertain ties (1 sigma) are within the pre-launch specification of 30%. Further improvements depend on characterization of the in-orbit RSRF improved performance of ISO pointing, and new data processing techniques.