Diagram illustrating the process of determining the visibility of surface elements of star A, which is partially covered by star B during the eclipse. Green surface elements are fully visible to the observer, whereas grey elements are considered to be hidden. Pink (and red) are partially visible surface elements based on the algorithm described in Sect. 8. The treatment of partially visible surface elements is demonstrated on the example of a surface element marked in red. A substantial increase in precision was achieved with the calculation of the overlapping area of the surface element marked in red.