Hi Ed, > ] Giotto's orbital elements with respect to the ecliptic are: > ] Semi-major axis - 1.0827 AU. (period 1.127 years) > ] Eccentricity - 0.081274. > ] Inclination - 5.5353 deg. > ] Longitude of ascending node - 279.111 deg. > ] Argument of perihelion - 313.2221 deg. > ] True anomaly - 339.4604 deg. ^^^^ Mean anomaly will be more useful to to calculations about ephemerides... Are these elements J2000 or "mean" equator and ecliptic of the date ? Regards, Raoul ----- Observatoire de Genève Raoul Behrend CH-1290 Sauverny / Suisse Raoul.Behrend@Obs.UniGe.CH http://obswww.unige.ch/~behrend "Herbe à Nicot? Herbe à nigaud!"