  SDSS (DR1 and DR2) has recently proposed 7 new DO white dwarfs as well as 6
new PG1159 stars. This is a significant increase in the known number of DOs and
PG1159 stars. Our spectral analyses provide stellar parameters which can then
be used to derive constraints for the evolution of H-deficient white dwarfs. A
comprehensive understanding of these objects is still severely hampered by
low-number statistics.
