The central angle is also known as the arc's angular distance. As the angular distance from the guide star increases, the image quality degrades. The companion has an apparent brightness of 7.3 at an angular distance of 3.2 arcseconds. The Moon's elongation is its angular distance east of the Sun at any time. The amplitude of a saccade is the angular distance the eye travels during the movement. Bounded elongation is the angular distance of celestial bodies from the center of the universe.