  We present a grid of nova models that have an extremely large number of
species treated in non-LTE, and apply it to the analysis of an extensive time
series of ultraviolet spectroscopic data for Nova Cygni 1992. We use
ultraviolet colors to derive the time development of the effective temperature
of the expanding atmosphere during the fireball phase and the first ten days of
the optically thick wind phase. We find that the nova has a pure optically
thick wind spectrum until about 10 days after the explosion. During this
interval, we find that synthetic spectra based on our derived temperature
sequence agree very well with the observed spectra. We find that a sequence of
hydrogen deficient models provides an equally good fit providing the model
effective temperature is shifted upwards by ~1000 K. We find that high
resolution UV spectra of the optically thick wind phase are fit moderately well
by the models. We find that a high resolution spectrum of the fireball phase is
better fit by a model with a steep density gradient, similar to that of a
supernova, than by a nova model.
