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Дата индексирования: Sat Sep 11 20:24:44 2010
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Calar Alto 2.2m telescope observations

Follow-up spectroscopy with the CAHA 2.2m telescope was carried out during two runs (June and December, 1999, see Table 2), using the Calar Alto Faint Object Spectrograph (CAFOS) and Cassegrain focal reducer. During these runs a long slit of $300\arcsec \times (2\arcsec-3\arcsec)$ and a G-200 grism (187Åmm^-1, first order) were used. The B-200 grism (185Åmm^-1, first order) was also used to reobserve 18 objects in order to improve the [O II]$\lambda$3727Å value. There were no order separation filters applied. The spatial scale along the slit was $0\farcs53$ pixel^-1. A SITE 15 2K$\times$2K CCD was operated in a 2$\times$1 binned mode during the December run (binning only along the dispersion direction), while in the June run there was no binning applied. The wavelength coverages were $\lambda$3700 - $\lambda$9500Å with maximum sensivity at $\sim$ 6000Å for the G-200 grism and $\lambda$3500 - $\lambda$7400Å with maximum sensivity at $\sim$ 4000Å for the B-200 grism. The spectral resolution was $\sim$ 10Å (FWHM) in the June run and due to CCD binning $\sim$ 20Å (FWHM) in the December run. The slit orientation was not aligned with the parallactic angle because of the snap-shot observing mode. The exposure times varied within 2-15 minutes depending on the object brightness. The observations were complemented by standard star flux measurements (Oke [1990], Bohlin [1996]), reference spectra (Hg-Cd lamp) for wavelength calibration, dome flat, bias and dark frames. Most of the time the weather conditions were photometric with a seeing $\approx$1.5 (FWHM). Only during two nights the weather conditions were variable with a seeing of 3 - 4(FWHM). The measurements of these nights are marked by ``*'' in Table 4.