Astron. Astrophys. 332, 928-938 (1998)

2. Observations and data reductions

The chemical analysis of the programme stars is based on an accurate study of high-resolution optical spectra ( / =50000, corresponding to a projected slit of 1.1"). The spectra have been obtained by one of us (EJB) with the Utrecht Echelle Spectrograph, fed by the 4.2m William Herschel Telescope at La Palma, Spain. The echelle spectrograph is equipped with a cross-dispersor so that the different orders are projected next to one another on the CCD. In the red part of the spectrum the consecutive orders are not overlapping. The wavelength coverage of the spectra is indicated in Table 1. The data were reduced using the echelle package of IRAF V2.9 in a standard way with optimal extraction of the orders.

© European Southern Observatory (ESO) 1998

Online publication: March 30, 1998
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