1863 20160701171654.0 10.1051/aas:1998151 DOI ASTROimport-20 de Cuyper, J.-P. 1998 Wavelength calibration at moderately high resolution 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 >1000nm for use at pixel-scales between lambda /2.510(4) and lambda /10(5) . Full Tables 5 and 6 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract. html Hensberge, H. Astronomy and Astrophysics Supplement Series 128 1998 409-416 http://esoads.eso.org/abs/1998A%26AS..128..409D published in REFERD