To supplement the spacecraft observations of comet P/Halley 1986 III a detailed ground-based observing program was conducted at the European Southern Observatory. The observations aimed at the determination of the spatial distribution of the most interesting neutral and ionic coma constituents which show emissions in the near-UV and blue spectral ranges. Within this program the focal reducer of the Observatory Hoher List, augmented and adapted to comet observations with instrumentation provided by the Max-Planck-Institut für Aeronomie was used at the European Southern Observatory 1 m telescope between March 10-16 and April 4-11, 1986. As detector an image intensifier was chosen because at the observed wavelengths it had a better sensitivity than the CCD cameras available at that time. For permanent recording photographic plates were used.
The observational data consist of direct filter images and multislit spectra. A set of direct images obtained on April 11, 1986, was analysed by Jockers et al. (1987). The present paper is concerned with the data reduction and analysis of multislit spectra taken on April 10, 1986. With the multislit technique it was possible to obtain 69 spectra, each from a different part of the cometary coma, at the same time.
The spectra show a large number of emission features
due to different coma constituents. The analysed emissions
originate from the molecular ions 
, 
and the neutral radicals CN,
, and CH. Radial profiles and two-dimensional maps, which
describe the spatial distribution of these species and of the dust continuum,
are deduced from the spectra. The spatial distribution of the
neutral radicals is interpreted in terms
of the Haser (1957) model. The value of this paper, in our
opinion, rests in the information presented about the distribution of the
cometary ions and . Even 10 years after the
apparition of comet Halley such information has not been published
elsewhere. Also the results about the dust and the neutral radicals are
unique because the field of the employed instrument was well adapted to the
size of the cometary coma. Comparison of the data on neutral radicals with
data obtained by other authors provides confidence in our results which were
obtained the oldfashioned way with an image intensifier and recorded on
photographic plates. To our knowledge this is so far the only case where the
multi-slit technique has been applied to comet observations, but the
procedure is similar to the technique used in the TKS instrument flown on
the Vega spacecraft (Rousselot et al. 1994; Clairemidi et al. 1990). The results of this work can be used for comparison with
models of the abundance and spatial distribution of cometary constituents in
comet Halley and other comets.