Published online by Cambridge University Press: 01 October 2007
We describe a way to compare current relativistic astrometric models accurate to the micro-arcsecond level. The observed stellar direction can be written as a function of several parts, linking the astrometric observables to the relativistic effects associated to the stellar kinematical properties and distances as seen inside the gravitational field of our Solar System, i.e. the so called relativistic astrometric parameters, providing a tool for comparing the RAMOD framework to the pM/pN approaches.