On Calculation of the Atmospheric Dispersion to
            Positional Observations of Minor Planets
                    N.V.Narizhnaja
              Pulkovo astronomical observatory
     196140, Russia, Saint-Petersburg, Pulkovskoe sh., 65/1
    Most of the orbits of the selected minor planets from the
our observational program are situated near the ecliptic plane,
therefore these planets are observed at Pulkovo on the large
zenith distances. For the reduction of the photographic positi-
ons of minor planets in 1991-1994 the coordinates were obtained
with calculation atmospheric dispersion in position reference
stars and planets by method proposed in Pulkovo. 224 positions
of 9 minor planets (Ceres, Pallas, Juno, Hebe, Iris, Parthenope,
Melpomene, Laetetia, Industria) have been obtained at z=45-65 .
The minor planet spectra are choosed accordingly their color
index. Obtained results were compared with positions reduced by
method of eight constant without the calculation of atmospheric
dispersion.
    The calculation shown, that the sistematic deviations (O-C)
in RA were changed for the all planets insignificantly. In (O-C)
DE chromatic deviations amount to  0.13". These values have a
good agreement with the variations of zenith distances on which
coresponding minor planets were observed.  For most of the minor
planets the observed positions calculated  with atmospheric dis-
persion were aproached to ephemeris.