  Within the framework of the German Astrophysical Virtual Observatory (GAVO),
we provide synthetic spectra, simulation software for the calculation of NLTE
model atmospheres, as well as necessary atomic data. This will enable a VO user
to directly compare observation and model-atmosphere spectra on three levels:
The easiest and fastest way is the use of our pre-calculated flux-table grid in
which one may inter- and extrapolate. For a more precise analysis of an
abservation, the VO user may improve the fit to the observation by the
calculation of individual model atmospheres with fine-tuned photospheric
parameters via the WWW interface TMAW. The more experienced VO user may create
own atomic-data files for a more detailed analysis and calculate model
atmosphere and flux tables with these.
