A document from a monastery in Egypt has turned out to be a treasure. The astronomer Hipparchus is thought to have been the first person to map the entire sky.

Hipparchus's catalog has been searched for by scholars for hundreds of years. James Evans is an astronomer at the University of Puget Sound in Washington. This week's Journal for the History of Astronomy contains the extract. Hipparchus, considered the greatest astronomer of ancient Greece, did map the heavens centuries before other attempts. Astronomers shifted from simply describing the patterns in the sky to measuring and predicting them during the birth of science.

The manuscript came from the Greek Orthodox St Catherine's Monastery in the Sinai Peninsula, Egypt, but most of its 146 leaves are now owned by the Museum of the Bible. The Codex Climaci Rescriptus was written in the tenth or eleventh century. The codex is the best palimpsest, because it was cleaned so that it could be used again.

In 2012 biblical scholar Peter Williams at the University of Cambridge, UK, asked his students to study the older writing as a summer project. A passage in Greek attributed to the astronomer Eratosthenes was found by one of them. The pages were re-analyzed using the latest technology. Researchers at the Early Manuscripts Electronic Library in Rolling Hills Estates, California, and the University of Rochester in New York took 42 photographs of each page in different wavelength of light, and used computers to find combinations of frequencies that enhanced the hidden text.

Star signs

According to the style of writing and the dating of the material, it was transcribed in the fifth or sixth century. There are star-origin myths by Eratosthenes and a famous third-century-BC poem calledPhaenomena. Williams noticed something different when he pored over the coronaviruses images. The French national scientific research centre in Paris was the site of the alert. The person says he was excited from the beginning. We had star coordinates.

A page long is how long the surviving passage is. It gives coordinates for the stars at their extreme north, south, east and west, as well as the length and breadth of the constellation.

There are several lines of evidence pointing to Hipparchus as the source. The team was able to date the observations because of the accuracy of the astronomer's measurement. The position of the stars in the sky is affected by the phenomenon of precession, in which Earth slowly wobbles on its axis. The researchers were able to use this to check when the ancient astronomer must have made his observations, and found that the coordinates fit around 129 BC.

The only star catalogue that had survived from antiquity was compiled in Alexandria, Egypt in the second century AD. For more than 1,200 years, a mathematical model of the universe was accepted as a result of his work. The coordinates and magnitudes of more than 1000 stars were given by him. Hipparchus, who worked on the Greek island of Rhodes, is said to have been the first to measure the stars.

Location, location, location

The positions of some stars around the zodiac were previously measured by the Babylonians. Hipparchus was the first to define the locations of stars using two coordinates. Hipparchus was the first to discover Earth's precession and he modelled the motions of the sun and moon.

In a medieval Latin manuscript called the Aratus Latinus, the coordinates for three other star constellations must have come from Hipparchus. The historian of astronomy at the Free University of Berlin says that the new fragment makes it clear. The star catalogue that has been hovering in the literature has become very concrete.

Hipparchus would have included observations of nearly every visible star in the sky according to the researchers. He must have used a dioptra, or armillary sphere, if he didn't have a telescope. It shows the amount of work that has been done.

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Hipparchus and Ptolemy have a complicated relationship. Hipparchus's catalog is thought to have never existed. Ptolemy was accused of stealing Hipparchus's data and claiming it as his own. Hipparchus was thought to be the great discoverer by many people, whereas Ptolemy was thought to be the great teacher.

The team concluded that Ptolemy did not copy Hipparchus's numbers. Hipparchus's observations seem to be more accurate, with the coordinates read so far right. Ptolemy's coordinate system was based on the ecliptic, but Hipparchus used a different system.

Birth of a field

Evans said the discovery enriched the picture of Hipparchus. It shows us a glimpse of what he did. In doing so, it sheds light on a key development in Western civilization, themathematization of nature, in which scholars seek to understand the Universe shifted from simply describing the patterns they saw to aiming to measure, calculate and predict.

Hipparchus was responsible for turning astronomy into a predictive science. Hipparchus criticized earlier writers for not caring about numerical accuracy in their visions of the moon and stars.

He is thought to have had access to hundreds of years of Babylonian astronomer's observations. The Babylonians had no interest in modelling how the Solar System was arranged in three dimensions, but they did make accurate observations and developed mathematical methods to model and predict the timing of lunar eclipses. The Greek geometric approach merged with the tradition of Hipparchus.

The researchers hope that as they improve their techniques, they will be able to find more star coordinates. Some parts of the Codex Climaci Rescriptus are still not understood. There are more than 160 palimpsests in the St Catherine's library. Drug recipes, surgical instructions and a guide to Medicinal Plants are some of the previously unknown Greek medical texts.

There is a rich new seam of ancient texts in archives around the world. There are thousands of palimpsests in European libraries. There is a research possibility that can be applied to thousands of manuscripts with amazing discoveries.

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