Hipparchus of Rhodes – Ancient Astronomy’s Unrivaled Pioneer

Hipparchus of Rhodes was among the greatest scientists of the ancient times and definitely most significant personalities of Rhodes island. He was born more than 2,200 years ago with his birth year of around 190 BC. His place of birth was the city of Nicea in Ancient Greece. The city’s ruins remain to be seen to this day in the Turkish town of Iznik. Hipparchus is also often referred to Hipparchus of Nicea to reflect his place of birth. He is also called Hipparchus of Rhodes since it seems that he worked and lived for most of his life on the island of Rhodes.

There is no way to tell exactly what Hipparchus really looked like since there were only portrayals made long after he passed away. It seems that Nicea was proud of Hipparchus as his image was placed on coins between the years 138 and 253 AD. It means that the first coins that honored Hipparchus were minted around 250 years following his death.

Contributions to Astronomy and Trigonometry

Hipparchus was able to accurately measure the distance between the earth and the moon.  He was also the founder of the trigonometry’s mathematical discipline with his combinatorics work considered to be unrivalled until 1870. 

It was also him who observed a nova, the appearance of a brand new star, as well as the precession of equinoxes. Hipparchus suspected that the stars might move little by little in relation to one another over long periods of time. He also nursed the hope that people in the future will be able to verify this. This is the very reason why Hipparchus compiled the star catalog that documented the magnitudes and positions of more than 850 stars. His legacy also bore fruit at about two millennia later when Edmund Halley was able to discover the correct motion of stars in 1718.

There are times when Ptolemy, the great astronomer himself, literally quoted Hipparchus so people can still read some of the direct thoughts of Hipparchus.

Surviving Works and Historical Challenges

Only a few of the original work of Hipparchus has survived. The only way that people was aware of some of his most vital discoveries and observations was because of the comments on them of other ancient scholars or how they also used Hipparchus’ works in their very own works.  

It is not uncommon to have limited information regarding the life of Greek mathematicians. With Hipparchus, however, the position is a bit unusual because even if he was an astronomer and mathematician of major importance, there were very few definite details regarding his work. Commentary on Aratus and Eudoxus was the sole surviving work of Hipparchus and this is definitely not among his major works. However, it is important since it gives people the only source of the own writings of Hipparchus. Majority of the details regarding Hipparchus’ work comes from Almagest of Ptolemy.

hipparchus of rhodes coin

Legacy and Rediscoveries

When 1870 came, Ernst Schroeder revealed the Schröder numbers’ concept, his newest discovery. No one realized that 2,000 years earlier, Hipparchus, the greatest the astronomers of antiquity, was using the numbers already!


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About the author

I have been working in the tourism industry more than 10 years, gaining experience in tour operating, transportation and accommodation. As a seasoned tour leader, I am passionate about developing tourist services and making them unique experiences. In addition to tour leader job, I am also involved in digital marketing and article blogging. Outside of the office, I enjoy travelling, photography and enriching my knowledge with new skills.

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