When it comes to finding or inventing concepts in mathematics, some of the renowned astronomers or mathematicians are the Greeks.
There is one person because of whom we get to hear the three words: Sine, Cosine, and Tangent. These 3 terms signify one of the most interesting concepts of mathematics: Trigonometry.
The person who discovered this was the Great Greek astronomer, geographer and mathematician, Hipparchus. Hipparchus was born in 190 BC in Nicaea, Bithynia. He was one of the greatest scientists of antiquity, but only one of his writings is still in existence. He wrote second-hand reports in the great astronomical compendium, the Almagest, written by Ptolemy in the 2nd century. Hipparchus is not only famous as the founder of trigonometry, but also for the discovery of the precession of the equinoxes. Earth's precession is called the precession of the equinoxes because the equinoxes move westward along the ecliptic relative to the fixed stars, opposite to the yearly motion of the Sun along the ecliptic.
Career and Qualifications
Hipparchus not only found trigonometry but also constructed the trigonometry tables, solved spherical trigonometry, and used the solar and lunar theories along with trigonometry, to develop a reliable method to predict solar eclipses. His other achievements include the compilation of the first comprehensive star catalogue of the Western World and the invention of the Astrolabe. Hipparchus is also referred to as the Father of Astronomy.
Hipparchus measured the length of the year to be 6.5 minutes, and with the help of this discovery, he found the precession of the equinoxes. He found the value of 46” for the annual precession when currently the value is 50.26”, which is much closer and better than the value which was found by Ptolemy of 36” 300 years later. It is believed that Hipparchus's star catalogue contained about 850 stars, which was probably completed in 129 BC, and has been claimed to have been used by Ptolemy as the basis of his star catalogue. However, considering the Commentary on Aratus and Eudoxus, it is certain that without the positions of the stars given by Hipparchus, Ptolemy’s star catalogue could not have been made.
Birth to Death
Hipparchus was born in 190 BC and throughout his life, he discovered many things and wrote many books. However, the only work of Hipparchus which has survived is the Commentary on Aratus and Eudoxus. Most of his work comes from Ptolemy's Almagest. Two commentators were expected to write about Hipparchus but they failed to gather relative information. It is considered that neither of them had access to the information about Hipparchus on which the public would have liked them to report.
Hipparchus has contributed a lot to the world of mathematics, but along with that, he is the only Greek mathematician who found the trigonometric tables and solved the spherical triangles. Little is known about his life, but one of the things which are of utmost importance is that his calculations were based on an ellipse that occurred on 14th March, 190 BC.
By Megh Dedhia
https://www.britannica.com/biography/Hipparchus-Greek-astronomer
Interesting facts about one of our renowned Mathematicians and his contributions.