High precision astrometry
Trajectory of a light ray (the effect is heavily exaggerated in the image)
Since the theoretical and technological realization of the modern astrometry in the micro-arcsecond regime (see Gaia-Mission) the next step of accuracy is the sub-micro and even nano-arcsecond regime. Current research therefore aims towards making measurements in this regime possible. Such ultra-high precision measurements are considered to be a key tool to the progress of astrophysics.
The central objective in this research topic is the analytical solution of the equations describing the light trajectory from the source to the observer through the gravitational field of the solar system.