Ratios of the lunar flux to the planetary flux F_m/F_p computed according to Eq. (A.1). F_m/F_p depends on the ratio of the lunar to the planetary radius r_m/r_p and the ratio of the geometrical albedoes A_m/A_p. Contour lines indicate equal flux ratios. Symbols indicate values for planet-moon pairs in the Solar System at a wavelength of 549 nm. The different planets are marked by different symbols; moons are indicated by their first letter(s). Circumplanetary rings are not included in the calculation. All values are from the NASA planetary fact sheets (D. R. Williams, https://nssdc.gsfc.nasa.gov/planetary/planetfact.html, as of May 7, 2024). Abbreviations of the moons: Earth: M (The Moon); Jupiter: I (Io), E (Europa), G (Ganymede), C (Callisto); Saturn: M (Mimas), E (Enceladus), TE (Tethys), D (Dione), R (Rhea), TI (Titan); Uranus: Ariel (A), Umbriel (U), Titania (T), Oberon (O), Miranda (M); Neptune: Triton (T), Nereid (N), Proteus (P); Pluto: Charon (C).