On Purple Mountain Halpha observations of SS 433
  In this brief note I draw attention to the structure of the stationary Halpha
line as a function of orbital phase, using a data set compiled over some years.
These data are compared with a set of nightly observations over some 2 orbits.
The structures are very similar and this is highly relevant to the question of
persistence and stability of spectral features which have been attributed to a
circumbinary disk.
