2007A&A...471..335S

The recent improvements in ground and space observational techniques, as well as the launch of specific space missions such as Hipparcos, has considerably increased the precision of astrometric measurements. One of the most important goals still remaining is the link to the primary catalogue ICRF (International Celestial Reference Frame) and the dynamical reference determined through the time coordinates and the trajectories of moving celestial bodies, such as the Moon, the Sun, and the planets. In this paper we investigate how this link can be made through the close encounters between Jupiter and quasars. We prefer to focus on the period involving the future space mission GAIA, and also to determine the corrections due to the relativistic deflection of the light of the quasars around Jupiter. After defining the (α, δ) parallax effects between an Earth-based observational site and GAIA, we have obtained a large number of close encounters (232 between 2005 and 2015, with a threshold of 500"). Then in order to show typical configurations of close encounters, we selected several cases among the most interesting grazing ones, insisting on the relativistic deflection of light as seen from the two observational sites. We conclude that these events deserve a lot of attention in the future, in particular in the scope of a link between the dynamical reference system and the ICRF.