Hipparchus of Rhodes was a renowned Greek astrologer whose mathematical computations to chart the sun, moon, and stars led to his being named the founder of trigonometry. Hipparchus is also considered the founder of Greek astronomy for his systematic approach to the discipline, which based it on a solid scientific foundation. In his book, the Almagest, the famous Greek astronomer and mathematician Claudius Ptolemy holds Hipparchus in the highest regard, referring to him as the "man who loved work and truth."

Details of Hipparchus' life remain lost. What little is known about him can be found in the writings of Strabo and Ptolemy. According to several ancient sources, Hipparchus was born in the city of Nicaea in a part of northwestern Asia Minor that is now Turkey. The era in which he lived has been determined primarily from the dates of his astronomical observations. In the Almagest, Ptolemyrefers...