The outer set of figures shows the corresponding phase as viewed from Earth, and the common names for the phases. The largest separation between the Earth and Moon on its orbit is called apogee and the smallest separation is called perigee. The planets, as viewed in the sky, exhibit characteristic aspects and phases. The terminology associated with these aspects and phases is different, depending on whether we refer to an inferior planet or a superior planet . The inferior planets exhibit the aspects and phases illustrated in the following diagram.
Gibbous phases are phases between quarter and full phases.
Greatest Elongation refers to the largest separation of the planet from the Sun in our sky, either to the East, or to the West. These aspects and phases are indicated in the following diagram. When a superior planet is at quadrature, it is on our celestial meridian at sunrise or sunset.