Total light deflection in the gravitational field of solar system bodies

Abstract: The total light deflection represents a concept, which allows one to decide which multipoles need to be implemented in the light trajectory for a given astrometric accuracy. The fundamental quantity of total light deflection is the tangent vector of the light trajectory at future infinity. It is found that this tangent vector is naturally given by Chebyshev polynomials. It is just this remarkable fact, which allows to determine strict upper limits of total light deflection for each individual multipole of solar system bodies. Special care is taken about the gauge terms. It is found that these gauge terms vanish at spatial infinity. The results are applied to the case of light deflection in the gravitational fields of Jupiter and Saturn.