A supernova which caught much attention in 1998 was the bright SN 1998S.
It was brighter than U = 12 at maximum, and was observed with a number of
telescopes, including the 
by SINS. SN 1998S was the third
core-collapse supernova (in addition to SNe 1987A and 1993J) for which
high-quality UV spectra were taken during an extended period of time.
Conspicuous circumstellar narrow lines were seen on top of the usual broad
components. It is evident that the supernova ejecta interact with a dense
stellar wind, presumably as dense as that around SN 1979C. Non-LTE
analysis of the early spectrum was performed, and this indicates that
Comptonization of the photospheric spectrum by hot electrons as a result of
circumstellar interaction is needed.