Greek astronomer and mathematician. He invented trigonometry and calculated the lengths of the solar year and the lunar month, discovered the precession of the equinoxes, made a catalogue of 850 fixed stars, and advanced Eratosthenes' method of determining the situation of places on the Earth's surface by lines of latitude and longitude.
The five points of the star represent the unity of farmers, workers, intellectuals, soldiers, and youth in establishing socialism. Red stands for revolution and bloodshed. Effective date: 2 July 1976.