Integrated phase function of Phobos from SRC observations. Top: opposition effect from integrated photometry from the five SRC orbits. The data presented in Fig. 2 have been normalized, and the radiance factor was estimated from the measurement with the green filters at α = 5°. Bottom: SRC phase function (black points) superposed on the Hapke global fit model. For completeness, some SRC data acquired during 2019–2020 at a higher phase angle are shown on the gray background, but these data were not used in the analysis.