Claudius Ptolemy was an Egyptian mathematician and astronomer of Greek origin. The text that came into the hands of scientists was written in the 1st century AD.

What was in the manuscript

• Written in Greek on parchment, the text was first discovered in 1819 in the library of the Abbey of Bobbio in northern Italy by Angelo Mai, a cardinal and a scholar of antiquities.
• Because parchment was so expensive at the time, someone in the 6th or 7th century AD wrote another text on Ptolemy’s manuscript – the “Etymology” of the Spanish theologian Isidore of Seville.
• Already in modern times they have tried to delete this text.
• Finally, the parchment was ruined.

Modern researchers have turned to the multispectral visualization method. The basic idea is that different wavelengths of light look different on a page written with ink of different composition. It was this method that made it possible to read more than half of what was written.

It turned out to be a handbook written by Ptolemy describing how to build a meteoroscope, a tool for tracking distances and studying stars. The scientist recommended designing an instrument with a diameter of at least 0.3 meters.

Meteoroscope / Photo: Victor Gysembergh

Unfortunately, The author’s name is missing, as the first and last pages of the manuscript are missing., says Alexander Jones, one of the study’s authors. But Ptolemy’s Greek texts have a special style – he uses certain phrases and words that no one else uses in all of ancient Greek literature. There is also a passage in the text where the author speaks in the first person: “I introduced new terminology for certain angles used in astronomy”.