Astron. Astrophys. 344, 277-281 (1999)

2. Observations and data analysis

Our group first observed Hen 3-640 in March and July 1985, at ESO La Silla with the 1.52m telescope equipped with the B&C spectrometer and IDS detector, using a 4 arcsec slit; the seeing was always better than 2 arcsec. The data were reduced at ESO (Garching), using IHAP . Then, a long term monitoring started in February 1990 (and it is still in progress) at the CASLEO (Argentina) 2.15 m telescope. This telescope was equipped up to 1993 with a B&C spectrograph; an Intensified Photon-Counting Reticon ("Z-machine"; Tonry & Davis, 1979; Da Costa et al., 1984) was used as detector. The instrumental configuration and the related data reduction process were described in Villada et al., (1992). Since 1994 the telescope was equipped with a REOSC echelle spectrogaph on loan from the Institute d' Astrophysique de Liege and a TEX 1024 CCD detector. During our observations, the seeing was always better than the slit size (3 arcsec or 5 arcsec, depending from the seeing conditions).The data were reduced at the Observatorio de la Universidad de Cordoba and at the Istituto di Astronomia of the Rome University "La Sapienza" , using standard IRAF procedures. Table 1 gives the log of the observations discussed in this paper.

Table 1. Hen 3-640: log of the observations discussed in this paper.

© European Southern Observatory (ESO) 1999

Online publication: March 10, 1999
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