Abstract: A Spectrograph’s Instrumental Profile and Scattered Light. Model Atmospheres and Spectrum Synthesis, 5th Vienna Workshop,

With the advent of high signal-to-noise detectors on high resolution spectrographs, new emphasis is being placed on two often ignored factors, the instrumental profile and scattered light. The general characteristics of both are reviewed and some specific examples are discussed. An unsuccessful attempt to determine the scattered light contribution by comparison of an FTS solar spectrum with a sky spectrum is described. Finally the comparison of the observed Hgamma profile of Vega with a scanner profile is shown to produce satisfactory results.