  We present a long-slit spectrum of the Herbig-Haro object HH 111, obtained
with SITS on the Hubble Space Telescope. This spectrum has a spectral
resolution of approx. 50 km/s, so it gives a good picture of the kinematical
properties of the observed object at very high angular resolution. We find that
some of the knots along the jet are associated with sudden drops in the radial
velocity (modulus), confirming that the emission from the knots is formed in
shocks. We interprt the observed position-velocity diagrams in terms of a model
of a jet from a variable source, and we attempt to carry out a reconstruction
of the ejection variability necessary for reproducing the observed kinematical
structure.
