# Hipparchus of Nicaea

**Hipparchus of Nicea** , also known as **Hipparchus of Rhodes** , was an ancient Greek **mathematician** , **astronomer,** and **geographer** , considered by many historians to be a scientist of the highest quality and possibly the greatest astronomical genius among scientists who arose in ancient **Greece** . Most of his success was based on the **systematic exploitation of** the **knowledge** and different astronomical techniques of Chaldea and Babylon, many of his achievements in **astronomy** remained widely accepted during the seventeenth century.

**Personal information:**

**When was he born:**190 BC**Where he was born:**Nicaea, Bithynia**When he died:**120 BC**Where he died:**Rhodes, Greece

## Who was Hipparchus of Nicea?

Hipparchus of Nicaea is considered the world’s first **astronomer** and **scientist** , he was a precise man in his research and creator of the theory of the length of the year determined by the **seasons**.

## Biography of Hipparchus of Nicea:

Actually, very little is known about the life of Hipparchus, but it is known that he was born at **Nicaea** in **Bithynia** . The city of Nicea currently has the name **Iznik** and is located in northwestern **Turkey** . Founded in the 4th century BC, Nicea is located on the eastern shore of Lake Iznik. Reasonably, Hipparchus is known as **Hipparchus of Nicaea** or **Hipparchus of Bithynia** , and is listed among the famous men of Bithynia by Strabo. There are Nicaea coins depicting Hipparchus seated looking at a globe.and his image appears on coins minted under five different Roman emperors between AD 138 and AD 253 These aspects seem to place Hipparchus at Nicaea and, in fact, **Ptolemy** describes Hipparchus as an observer in Bithynia, which makes us think that he was actually observing at Nicaea. Only one work by Hipparchus has survived, namely the **Commentary on Aratus and Eudoxus** , and it is certainly not one of his major works. However, it is important because it provides us with the only source for Hipparchus’ own writing.

## Contributions:

Hipparchus of Nicaea made important contributions in the field of **plane** and **spherical ****trigonometry** . He published the **table of chords** , the purpose of which was to provide a new method for solving triangles. He also introduced the **division** of the **circle** into 360 degrees. In the area of astronomy he discovered the precession of the **equinoxes** and described the **movement** of **stars** that were supposed to be fixed. Another of his important contributions was that he managed to make calculations between the **distance** that there was with the **moon**based on the observation of an eclipse. His calculation was between 59 and 67 terrestrial radii, which is very close to the real one, which is 60 radii. He used and perfected the **geometric ****tools** that had been proposed by Apollonius of Perga to eliminate most of the contradictions in **the geocentric model.**

## Astronomy:

Hipparchus is considered the greatest **astronomer** of the time. He studied the **motion** of the **Moon** and confirmed precise values for some **periods** of its motion that Chaldean astronomers had obtained before him. It is believed that in Rhodes he managed to build an **observatory** , although very little is known about the instruments that I use. According to Ptolemy, Hipparchus managed to build a **theodolite** to measure angles and a diopter to measure the diameter between the sun and the moon. He made calculations regarding the length of the **seasons** and constructed a table showing the **position** of the **sun**. He made a catalog with 850 stars classified according to their **luminosity** . He calculated the **synodic** month , the **sidereal** month, and the **anomalous** month .

## Trigonometry:

Hipparchus is recognized as the first mathematician who created a **trigonometry table** , which he needed to calculate the eccentricity of the orbits of the Moon and the Sun. With his contributions, and with the creation of the **table of chords, he** allowed the Greek astronomers to solve any type of triangle, and allowed you to make **quantitative astronomical models** and **predictions** using your preferred geometric techniques. Hipparchus was one of the first Greek mathematicians to use Chaldean **arithmetic** techniques , and in this way expanded the techniques available to astronomers and geographers.

## Works of Hipparchus of Nicea:

One of his works was Hipparchus’s **catalog of stars** , which can be found in **Ptolemy’s Almagest** , in books VII and VIII. Another of his great works was the **rope board,** which was the equivalent of a modern breast board.

## Phrases:

There are not many famous phrases of Hipparchus of Nicaea recorded, but the following are recorded.

*Know yourself.**Nothing is too much.**He walks thinking only in thoughts.**Don’t cheat on a friend.*

## Importance of Hipparchus of Nicea:

The importance of Hipparchus of Nicea lies in his contributions to **science** . He was the creator of the foundations of **trigonometry** and the discovery of the precision of the **equinoxes** . Probably the most important contribution was in the field of **astronomy** , in which he managed to determine the sizes and the different distances between the **orbits** of the **sun** and the **moon**.