Io phase angle relative to the Sun for the observations detailed in this work. The position of Io is given as a small circle where the corresponding number refers to the case index given in Tables A.1–A.3. Red circles indicate that no jet-like structure was observed on this date, whereas a blue circle indicates that at least one jet-like structure was observed. The cases in purple are those for which Io is behind Jupiter or close to another moon, so non-detection during these observations may be due to the configuration of the system as well as the absence or faintness of the jet itself. Key phase angles, given in degrees, have been annotated around the diagram, as well as the position of the Sun in the diagram. Panel a: 2014-2015. Panel b: 2021. Panel c: 2022-2023.