Full context:   The Earth turns upon its own axis from West to East in 24 hours, so that the entire celestial sphere seems during this rotation to move from East to West, including those privileged members of the solar system called planets, the star that holds them in its field of gravity, and the Earth's satellite, the Moon. The daily movement of these bodies describes a sinusoidal curve with four phases, comparable to that which characterizes their Zodiacal movement: from the Ascendant to the Midheaven the celestial body rises above the horizon, from the Midheaven to the Descendant it travels down again, from the Descendant to the Nadir it declines below the horizon, from the Nadir to the Ascendant it rises, but this time below the horizon. These four phases define the diurnal and nocturnal semi-arcs of the body in question.