"First known map of night sky found hidden in Medieval parchment: Fabled star catalogue by ancient Greek astronomer Hipparchus had been feared lost."
https://www.heritagedaily.com/2022/10/r ... hus/145058
Nine folios revealed astronomical material, which (according to radiocarbon dating and the style of the writing) was probably transcribed in the fifth or sixth centuries. It includes star-origin myths by Eratosthenes and parts of a famous third-century-BC poem called Phaenomena, which describes the constellations. Then, while poring over the images during a coronavirus lockdown, Williams noticed something much more unusual. He alerted science historian Victor Gysembergh at the French national scientific research centre CNRS in Paris. “I was very excited from the beginning,” says Gysembergh. “It was immediately clear we had star coordinates.”
The surviving passage, deciphered by Gysembergh and his colleague Emmanuel Zingg at Sorbonne University in Paris, is about a page long. It states the length and breadth in degrees of the constellation Corona Borealis, the northern crown, and gives coordinates for the stars at its extreme north, south, east and west.
Several lines of evidence point to Hipparchus as the source, beginning with the idiosyncratic way in which some of the data are expressed. And, crucially, the precision of the ancient astronomer’s measurements enabled the team to date the observations. The phenomenon of precession — in which Earth slowly wobbles on its axisby around one degree every 72 years — means that the position of the fixed stars slowly shifts in the sky. The researchers were able to use this to check when the ancient astronomer must have made his observations, and found that the coordinates fit roughly 129 BC — during the time when Hipparchus was working.
Until now, says Evans, the only star catalogue that had survived from antiquity was one compiled by astronomer Claudius Ptolemy in Alexandria, Egypt, in the second century AD. His treatise Almagest, one of the most influential scientific texts in history, set out a mathematical model of the cosmos — with Earth at its centre — that was accepted for more than 1,200 years. He also gave the coordinates and magnitudes of more than 1,000 stars. However, it is mentioned several times in ancient sources that the person who first measured the stars was Hipparchus, who worked on the Greek island of Rhodes three centuries before, roughly between 190 and 120 BC.