What is parallax in simpler terms?
Parallax is just the viewing angle at two ends of a defined distance. The simplest explanation I can offer is watching an object at the center of a straight road (for example a car or another person) from two different sides of a road, noting the angle between object and center of the road on at least one side of the road. With these angles, you can construct a triangle. The angle you measured is the parallax. A parallax second (parsec) is the distance you get, when you measure a parallax of one arc second to an object, with a distance of 1 AU (distance Earth-Sun) to the center line and your observation.
