Previous abstract Next abstract In order to map the spatial
structure of a stellar atmosphere using Doppler imaging
techniques, observations of a rapidly-rotating star must be
obtained at all of its rotational phases. In order to
discriminate temporaral variability (e.g. flares) from phase-
locked variability (produced by magnetically-active regions on
the stellar surface), observations must be obtained over at
least two rotational cycles. Using the International Ultraviolet
Explorer, we observed the bright RS~CVn-type system HR~1099
(V711~Tau) continuously for two contiguous orbital/rotational
cycles (period$\sim$2.83~days) in December~1992. These
observations were coordinated with the 1992 campaign for Multi-
Site Continuous Spectroscopy (MUSICOS). The purpose of this
campaign was to coordinate a network of ground-based telescopes
distributed around the Earth so that moderate and high-
resolution spectroscopy could be obtained pseudo-continuously
for several days. Supporting photometric and radio observations