AbC is a compact on-board algorithm, initially intended for CubeSats, to measure the absolute direction of a distant beacon with optimised accuracy. The AbC environment anticipates a ground pipeline that has been used with OPS-SAT images to diagnose the ADCS. It has been shown that a ground-truth assessment of the satellite's orientation can be made which, with sufficient data, could allow precise re-alignment of multiple sensors. The ESA contract funded the implementation of the on-board algorithm in C++ and its pipeline in Python. A database of flight images was created to demonstrate the performance of AbC, which is still ongoing.