Astronomy and Astrophysics Letters dedicated to ISO

The wavelength calibration and resolution of the SWS.

Valentijn E.A., Feuchtgruber H., Kester D.J.M., Roelfsema P.R., Barr P., Bauer O.H., Beintema D.A., Boxhoorn D.R., de Graauw T., Haser L.N., Heske A., Heras A.M., Katterloher R.O., Lahuis F., Lutz D., Leech K.J., Morris P.W., Salama A., Schaeidt S.G., Spoon H.W.W., Vandenbussche B., Wieprecht E., Luinge W., Wildeman K.J.


The laboratory wavelength calibration of the SWS has been succesfully transferred to the in orbit situation. The achieved accuracies for the grating sections are {lambda}/{delta}{lambda}~10000. Any remaining errors in the wavelength scale are dominated by uncertainties of the relative position of the target in the 14"-20" wide slits. The grating spectral profile is very well represented by a Gaussian shape. The width of the grating spectral profile can be accurately predicted by a theoretical model. The wavelength calibration of the FP's is accurate to within 1/3 of a resolution element, corresponding to {lambda}/{delta}{lambda}~105. The wavelength stability of the gratings and FP is excellent, no measurable changes were found during the first 6 months of the ISO mission.

wavelength calibration, spectral resolution, infrared spectroscopy

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