^ Forward-scattered light is the light scattered at a small angle relative to the solar light (phase angle close to 180°).
^ Back-scattered light is the light scattered at an angle close to 180° relative to the solar light (phase angle close to 0°).
^ The normal optical depth τ of a ring is the ratio of the total geometrical cross-section of the ring's particles to the square area of the ring. It assumes values from zero to infinity. A light beam passing normally through a ring will be attenuated by the factor e−τ.[1]
^ The equivalent depth ED of a ring is defined as an integral of the normal optical depth across the ring. In other words ED=∫τdr, where r is radius.[2]
^ The rings' eccentricities and inclinations were taken from Stone et al., 1986 and French et al., 1989.[3][4]
^ The radii of the 6,5,4, α, β, η, γ, δ, λ and ε rings were taken from Esposito et al., 2002.[5] The widths of the 6,5,4, α, β, η, γ, δ and ε rings are from Karkoshka et al., 2001.[6] The radii and widths of the ζ and 1986U2R rings were taken from de Pater et al., 2006.[2] The width of the λ ring is from Holberg et al., 1987.[7] The radii and widths of the μ and ν rings were extracted from Showalter et al., 2006.[8]
^ The equivalent depth of the 1986U2R ring is a product of its width and the normal optical depth. The equivalent depths of the 6,5,4, α, β, η, γ, δ and ε rings were taken from Karkoshka et al., 2001.[6] The equivalent depths of the λ and ζ, μ and ν rings are derived using μEW values from de Pater et al., 2006[2] and de Pater et al., 2006b,[9] respectively. The μEW values for these rings were multiplied by the factor 20, which corresponds to the assumed albedo of the ring's particles of 5%.
^ The thickness estimates are from Lane et al., 1986.[10]
^ The normal optical depths of all rings except 1986U2R, μ and ν were calculated as ratios of the equivalent depths to the widths. The normal optical depth of the 1986U2R ring was taken from de Smith et al., 1986.[11] The normal optical depths of the μ and ν rings are peak values from Showalter et al., 2006.[8]
^ Off opposition means that the angle between the object-sun direction and object-Earth direction is not zero.
