space rotating on its tilted prism occurs once per twilight
erecting_prism is prism. astronomical_twilight is not twilight. orbiting is translational_vibration. zenith is celestial_point. triangular_prism is prism. twilight_zone is not ocean_floor. twilight_zone is ocean_floor. zenith is not celestial_point. astronomical_twilight is twilight. triangular_prism is not prism.