File:Stellarparallax Parsec1.svg
The apparent motion of a nearby star is a small ellipse in the sky relative to background stars over the period of a year. The viewpoint is defined as the Earth.
The angle representing major axis radius of the elliptical path is the parallax angle.
A parsec is defined as the distance to an object whose parallax angle = 1 arc second.Derivative works of this file: