  Context. Recently our ability to study stars using asteroseismic techniques
has increased dramatically, largely through the use of space based photometric
observations. Work has also been done using ground based spectroscopic
observations and more is expected in the near future from the SONG network.
Unfortunately, the intensity observations have an inferior signal to noise
ratio and details of the observations do not agree with theory, while the data
analysis used in the spectroscopic method has often been based on overly simple
models of the spectra. Aims. The aim is to improve the reliability of
measurements of the parameters of stellar oscillations using spectroscopic
observations and to enable the optimal use of the observations. Methods. While
previous investigations have used 1D models, I use realistic
magnetohydrodynamic simulations, combined with radiative transfer calculations,
to estimate the effects of the oscillations on the spectra. I then calculate
the visibility of the oscillation modes for a variety of stellar parameters and
using various fitting methods. In addition to the methods used in previous
investigations, I use a Singular Value Decomposition technique, which allows
one to determine the information content available from the spectral
perturbations and how that can be expressed most compactly. Finally I describe
how the time series obtained may be analyzed. Results. It is shown that it is
important to model the visibilities carefully and that the results deviate
substantially from models previously used, especially in the presence of
rotation. Detailed spectral modeling may be exploited to measure the properties
of a larger number of modes than possible using the commonly used
cross-correlation method. With moderate rotation, there is as much information
in the line shape changes as in the Doppler shift and an outline of how to
extract this is given.
