Workstation. The following steps were followed for the reductions:
The error in wavelength calibration for Coudé and Cassegrain spectra was around
0.05 Å to 0.10 Å respectively. To reduce the error in normalization we
normalized each spectrum, at least, three to four times and finally these
spectra were averaged. Around 2% of the local continuum is estimated to be
the error in normalization. The instrumental broadening was computed by
measuring the FWHM of the narrowest line of the comparison spectral lines and
this value of the FWHM was taken as the instrumental broadening of the
spectrograph. The values of instrumental broadening for the UAGS and the
Echelle spectrographs are 0.5 Å and 0.2 Å respectively, at H. These values were used to correct
for instrumental broadening of the measured FWHM values of Be stars. Using the
expression of
(EW), given in Ghosh (1988) and Ghosh et al. (1990), the
errors in equivalent width measurements were computed.
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Figure 1:
Coudé Echelle H![]() |
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