A mini catalogue of ultra-soft X-ray sources detected in 3
years of pointings with the ROSAT, and a programme for their
optical identification with many collaborators all over the world
has been initiated. These ultra-soft X-ray sources are found to
be predominantly white dwarfs, magnetic cataclysmic variables,
nearby late-type stars, and very X-ray soft active galactic
nuclei. Optical identification through spectroscopy, photometry
and polarimetry has already led to the discovery of two new
magnetic cataclysmic variables with unusual characteristics.
(K.P. Singh, P. Barrett [GSFC/NASA], N.E. White [GSFC/NASA],
P. Giomni [ESRIN, Italy] and L. Angelini [GSFC/NASA]).