Scholars found a long-lost star map from ancient Greek astronomer Hipparchus hidden beneath layers of medieval Christian text

The map, which was drawn on medieval parchment, is believed to be 2,000 years old.

• Scholars discovered the oldest known star map beneath the text of a Christian manuscript, according to new study.
• The long-lost catalog was developed by Hipparchus sometime between 162 and 127 BC.
• The ancient Greek astronomer made the earliest known attempt to chart the entire night sky.

Researchers believe they may have found a fragment of a long-lost star map compiled by the ancient Greek astronomer Hipparchus, who made the earliest known attempt to chart the entire night sky.  

In a paper published in the Journal for the History of Astronomy on Tuesday, scholars described discovering what they believe to be a 2,000-year-old segment of a star map. The text of a Christian manuscript was written on top of the map, which was drawn on medieval parchment. The Christian text came from Egypt's Saint Catherine's Monastery and is now in possession of the Museum of the Bible in Washington, DC. 

Hipparchus' star map, which was developed sometime between 162 and 127 BC, is the astronomer's attempt to record accurate positions of celestial objects with fixed coordinates.

Researchers say the star map was scraped away so the parchment could be reused — a common practice at the time. Using a technique called multispectral imaging, researchers took pictures of the parchment with different wavelength cameras and were able to decipher layers of text that had been scraped off.

The imaging technique revealed numbers stating the length and width of the constellation Corona Borealis in degrees, and coordinates for the stars at the constellation's farthest corners.

"I was very excited from the beginning," Victor Gysemberg, the study's lead researcher and a science historian at the French National Center for Scientific Research in Paris, told Nature. "It was immediately clear we had star coordinates."  

The "new evidence is the most authoritative to date and allows major progress in the reconstruction of Hipparchus' Star Catalog," the study authors wrote.

In addition to compiling the first known star catalog, Hipparchus is credited with being the first person to observe the Earth's precession — meaning how it wobbles on its axis — as well as the first to develop accurate calculations about the motions of the Sun and moon.