A&A Supplement series, Vol. 127, Mars I 1998, 409-416
Received January 24; accepted July 11, 1997
J.-P. De Cuyper and H. Hensberge
Send offprint request: J.-P. De Cuyper, Jean-Pierre.DeCuyper@oma.be
Royal Observatory of Belgium,
Ringlaan 3, B-1180 Brussel, Belgium
Th-Ar lamps are commonly used as wavelength calibration units at
moderately high spectral resolutions because
of the richness of the Th spectrum in the visual. The inclusion of blended
lines whose position is assumed to coincide with the laboratory wavelength of
the principal component is shown to result in a calibration precision
significantly worse than the intrinsic random noise limit. In order to
avoid this degradation of the calibration,
we present resolution-dependent Th-Ar wavelengths
in the region 277 to for use at pixel-scales between
and
.
keywords: methods: data analysis; techniques: spectroscopic