Report of the session of the WG on Natural Satellites
         Manchester, IAU GA, August 2000

J.E. Arlot gave some news from the Natural Satellite Data Center (NSDC)
especially of the database designed to provide astrometric observations,
theoretical models of the motions and ephemerides of the Natural Planetary 
Satellites through the Web server (http://www.imcce.fr/nsdc.html). 
During the past triennum, the data base was mainly feed with old and recent
observations made in the countries of the former SU thanks to N. Emelianov
and not yet made available to the astronomical community.
Improvements have also been made to the ephemerides service. Projects are 
now to evaluate the accuracy of the observations and the precision of the 
ephemerides and also to provide a standard reduction procedure for the
astrometric observations.

Activities and projects in some countries were also presented.

D. Pascu, from USNO, reviewed the satellites observable from the ground
and detailed the observations made at USNO.

A. Andrei presented a report made by R. Viera Martins from Rio de Janeiro.
Most of the Natural Planetary satellites were observed with the LNA 
1.6m telescope and observations will be continued.

R.A. Jacobson, from JPL, T. Nakamura from Japan and N. Emelianov from 
Moscow were not able to attend the GA and a report on their activities was
provided to the participants: R.A. Jacobson reviewed the sources of the
ephemerides used at JPL, T. Nakamura reported on the observations made at 
Kiso Observatory with a Schmidt telescope and on theoretical work on the
motion of Nereid and N. Emelianov reported on the observations of
satellites made in the observatories of the FSU.

J.E. Arlot presented the activities in France: reduction and publication
of the results of the campaigns of observation of the mutual events of the 
saturnian satellites in 1995 and of the galilean satellites in 1997 and
of the astrometric observations of the outer satellites of Jupiter and Saturn;
theoretical works on the satellites of Neptune N1, N2 and N3.

G. Williams, from the MPC, who was coopted as a new member of the working group,
gave informations on the newly discovered satellite of Jupiter by Spacewatch:
the object was first supposed to be a minor planet but the orbit appears to be
jovicentric instead of heliocentric. In order to help the observers of
minor planets, the elements of the orbit were published under the MPC format.

At last, a discussion came around several questions:
-how to avoid that observations remain unpublished? or published without
any sufficent explanations on the observation technique and on the
reduction procedure? 
-J.E. Arlot invited the observers to avoid a reduction procedure using
the ephemerides of the observed satellites themselves: it introduces
biases in the scale and orientation of the field and the models fitted
on these observations will have their accuracy degraded.