pub fn saturnshine_irradiance_lux(saturn_phase_fraction: f64) -> f64 {
0.3 + 3.0 * saturn_phase_fraction.clamp(0.0, 1.0)
}
pub fn dark_side_visibility_index(saturn_phase_fraction: f64, terrain_albedo: f64) -> f64 {
saturnshine_irradiance_lux(saturn_phase_fraction) * terrain_albedo.clamp(0.0, 1.0)
}