Summary of the associations carried out by Fink-FAT. Each night is represented by a vertical dashed night denoted N_i. Alerts are represented by colored circles. The color-coding describes a type of association, shown in the legend of the plot. The association step in Fink-FAT uses a sequential algorithm (1 → 2 → 3 → 4); therefore, the association order is important, especially since the previous step will remove the associated elements (trajectories, intra-night trajectories or single alert) from the possible association for the next steps. The first step (1) is the association between the trajectories built from the previous night’s alerts with the intra-night trajectories constructed during the current night. The second step (2) is the association between the trajectories and the remaining single alerts after the intra-night trajectories creation. The third (3) and fourth (4) steps are similar, as they associate past alerts with current ones. The third step associates the intra-night trajectory’s extremity with the old alerts. The fourth step associates current non-associated alerts with old alerts. The fourth step is one of the ways to start a trajectory as the intra-night trajectory building step. Note: each step can produce internally different trajectories including the same alert, as shown with the double association (3) at the bottom.