Illustrates the phenomenon known as parallactic proper motion. This simulation illustrates the phenomenon known as parallactic proper motion. Proper motion refers to the progressive (non-oscillatory) apparent motion of a star relative to more distant background stars. If this apparent motion is due to actual motion of the star through space then it is known as "true proper motion." However, this apparent motion can also be due to the motion of Earth (along with the Sun and the rest of the solar system) through space. This motion is known as "parallactic proper motion." In 1783 William Herschel detected parallactic proper motion in several stars and used these motions to determine that the solar system was moving toward a point called the "Solar Apex" in the constellation Hercules.

Requirements:
* Java

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