Comparison plot demonstrating the improved signal from applying the combination method for the species Fe I. Left panel: K_p – V_sys map of a single transit observation, this specifically is the first HARPS-N transit. The red border marks the window where the average signal strength is computed, and the region outside where the standard deviation is computed. Right panel: K_p – V_sys map when combining all four transit observations. The result is a much higher S/N.