  Advancement in astronomical observations and technical instrumentation
requires coding light propagation at high level of precision; this could open a
new detection window of many subtle relativistic effects suffered by light
while it is propagating and entangled in the physical measurements. Light
propagation and its subsequent detection should indeed be conceived in a fully
relativistic context, in order to interpret the results of the observations in
accordance with the geometrical environment affecting light propagation itself,
as an unicum surrounding universe. One of the most intriguing aspects is the
boost towards the development of highly accurate models able to recon- struct
the light path consistently with General Relativity and the precepts of
measurements. This paper deals with the complexity of such a topic by showing
how the geometrical framework of models like RAMOD, initially developed for
astrometric observations, constitutes an appropriate physical environment for
back tracing a light ray conforming to the intrinsic accuracy of space-time.
This article discusses the reasons why RAMOD stands out among the existent
approaches applied to the light propagation problem and provides a proof of its
capability in recasting recent literature cases.
