All observations were made with the 2-m RCC telescope of the Bulgarian
National Astronomical Observatory during 1994 and 1996. The Third Camera of
the coudé spectrograph and the 580 
520 ISTA CCD matrix with a
pixel size 24 18 
m were used. The entrance slit of 300 m
corresponding to 0.8 arcsec was set to provide a spectral power of 30000.
With a 632 mm-1 Bausch & Lomb grating, a spectral range of
6675 - 6725 ÅÅ was covered with a dispersion of 4.2 Åmm-1 and
a resolution of 0.22 Å. No binning was used. The reference spectrum was
provided by a hollow-cathode Fe-Ar lamp. Flat-field frames were made
by using a tungsten lamp. A shortened version of the log book is presented in
Table 1 (click here). The PC-based IPS software package (Smirnov et al.
1992) was used for the flat-field correction, normalization and
wavelength calibration. Consequently, for each star, we applied the spectra
co-addition technique proposed by Hill & Adelman (1986).
As a result the S/N ratio of about 250 for HD108651, 350 for HD116657
and 300 for HD138213 was reached at the 
level.
| HD | Date | Time | Exp. |
| 108561 | 3.3.1996 | 23:50 |  |
| 7.4.1996 | 00:10 |  | |
| 31.5.1996 | 19:00 |  | |
| 1.6.1996 | 21:00 | | |
| 26.7.1996 | 19:10 | | |
| 116657 | 31.7.1994 | 18:40 |  |
| 26.7.1996 | 20:10 |  | |
| 27.7.1996 | 20:10 | | |
| 138213 | 30.7.1994 | 19:10 | |
| 31.7.1994 | 18:50 |  | |
| 25.7.1996 | 23:00 |  | |
| 26.7.1996 | 21:30 | | |
| 27.7.1996 | 21:30 | |