17 September 2025 The Future is the Product of the Past

Part of lost star catalog of Hipparchus found hidden in Medieval parchment

Hipparchus’ fabled star catalog, which had been thought to be lost, was discovered concealed in a medieval parchment that had originally been kept in the library of the Orthodox Monastery of St. Catherine in Sinai, Egypt.

Scholars have discovered what appears to be part of Hipparchus’ long-lost star catalogue — the earliest known attempt to map the entire sky — hidden beneath Christian texts.

Hipparchus, the Greek astronomer, is often referred to as the “Father of Astronomy.” Among other achievements, he is credited with discovering the Earth’s precession (how it wobbles on its axis) and calculating the motions of the Sun and Moon. According to historical texts, Hipparchus was also believed to be compiling a star catalog sometime between 162 and 127 BCE.

Scholars have been searching for that catalog for centuries. Now, thanks to a technique called multispectral imaging, they have found what seems to be the first known remnants of Hipparchus’ star catalog.

Multispectral imaging is a method that takes visible images in blue, green, and red and combines them with an infrared image and an X-ray image of an object. This can expose tiny pigment specks as well as concealed writings or drawings that have been covered up by several coats of paint or ink. For instance, researchers have previously used the method to uncover the hidden text on four fragments of Dead Sea Scrolls that were thought to be blank at the time.

The palimpsest was discovered at Saint Catherine's Monastery on the Sinai Peninsula in Egypt.
The palimpsest was discovered at Saint Catherine’s Monastery on the Sinai Peninsula in Egypt.

The extract is published online this week in the Journal for the History of Astronomy.

The current paper is the result of research into the Codex Climaci Rescriptus, a palimpsest that originated at Saint Catherine’s Monastery on Egypt’s Sinai Peninsula.

The majority of the manuscript’s 146 leaves, or folios, which originally belonged to the Greek Orthodox St Catherine’s Monastery in the Sinai Peninsula, Egypt, are now in the possession of the Museum of the Bible in Washington, DC. The pages contain the Codex Climaci Rescriptus, a collection of Syriac texts written in the tenth or eleventh centuries. But the codex is a palimpsest: parchment that was scraped clean of older text by the scribe so that it could be reused.

It was common practice at the time to scrape clean old parchment for reuse, and that’s what was done with the codex. Scholars initially believed the older writing to be more Christian texts. But in 2012, when Cambridge University professor and biblical expert Peter Williams assigned his summer students to study the pages for a special project, one of them found a Greek passage by the astronomer Eratosthenes.

Williams contacted researchers at the University of Rochester in New York and the Early Manuscripts Electronic Library in California to conduct multispectral imaging of the codex’s pages in 2017.

A leaf from the Codex Climaci Rescriptus in the Green Collection.
A leaf from the Codex Climaci Rescriptus in the Green Collection. Wikipedia

The method turned up a total of nine folios relating to astronomy that were written between the fifth and sixth centuries, including not only the passage by Eratosthenes on star myths but also a well-known poem (Phaenomena, written around the third century BCE) that describes constellations.

During the pandemic lockdown, Williams spent a significant amount of time studying the resulting images, and one day he noticed what appeared to be the coordinates of the constellation Corona Borealis. He immediately informed science historian Victor Gysembergh of the CNRS in Paris of his discovery.

“I was very excited from the beginning,” Gysembergh told Nature. “It was immediately clear we had star coordinates.”

But could Hipparchus be the author of this passage? The authors cite a number of pieces of evidence that appear to connect the text to the Greek astronomer, though they are hesitant to assign the text a specific attribution. For instance, some of the data are recorded in an odd way that is consistent with the only other piece of Hipparchus’s work that has been preserved. The observations recorded in the text were most likely made around 129 BCE, when Hipparchus would have been working on his catalog, according to the authors’ analysis of astronomical charts.

DOI: Journal for the History of Astronomy, 2022. https://doi.org/10.1177/00218286221128

Cover Photo: This cross-fade montage shows a detail of the palimpsest under ordinary lighting; under multispectral analysis; and with a reconstruction of the hidden text.Credit: Museum of the Bible (CC BY-SA 4.0). Photo by Early Manuscripts Electronic Library/Lazarus Project, University of Rochester; multispectral processing by Keith T. Knox; tracings by Emanuel Zingg.

Related Articles

2000-year-old quarry discovered in Jerusalem that could be the source of Second temple stones

5 September 2021

5 September 2021

Archaeologists have discovered a 2,000-year-old quarry in Har Hotzvim, now an industrial park in Jerusalem. The Israel Antiquities Authority said...

A 2,000-year-old wooden bridge that once linked England and Wales discovered

31 August 2023

31 August 2023

Archaeologists have discovered evidence of Roman and Anglo-Saxon fortifications in the town of Chepstow in the United Kingdom. Surprisingly, however,...

The Highest Prehistoric Petroglyphs in Europe Discovered at 3000 Meters in the Italian Alps

20 November 2024

20 November 2024

The highest petroglyphs in Europe were found at Pizzo Tresero (Valfurva) in the Stelvio National Park in the northern Italian...

The 1,000-year-old Church found under a cornfield in Germany

2 July 2021

2 July 2021

The foundation walls of the large church of the rediscovered Royal Palace of Helfta in Eisleben in the German state...

5,000-year-old Ceremonial Temple Discovered in Peru

9 July 2024

9 July 2024

Archaeologists from the Peru Ministry of Culture have discovered an ancient ceremonial temple complex at Los Paredones de la Otra...

Ancient Babylon Excavation Uncovers 478 Artifacts Including Cuneiform Tablets, and Cylindrical Seals

16 October 2024

16 October 2024

The Iraqi State Board of Antiquities and Heritage (SBAH) announced that 478 artifacts were uncovered during an excavation expedition in...

In Ryazan, the first birch bark letters were discovered

13 September 2021

13 September 2021

The first birch bark letters were found at the Vvedensky excavation site in the Kremlin in Pereyaslavl Ryazan (modern Ryazan)....

Floor Mosaic of the Early Byzantine Period Unearthed in St Constantine and Helena Monastery Church in Ordu

12 August 2024

12 August 2024

Republic of Türkiye Ministry of Culture and Tourism reported that an in-situ floor mosaic was found at the St Constantine...

An Urartian fortress was discovered at an altitude of 3,300 meters in eastern Turkey

2 July 2022

2 July 2022

In the Gürpınar district of Van, located in eastern Turkey, a fortress ruin, which is considered to be used by...

Unique Gold Artefacts of Thracian Horseman Found in Bulgaria

23 August 2024

23 August 2024

The Topolovgrad Municipality posted on its Facebook page on Wednesday that during excavations at the site of a Thracian warrior’s...

A new magnetic survey of the ancient Assyrian capital of Khorsabad has revealed a 127-room villa twice the size of the U.S. White House

26 December 2024

26 December 2024

Archaeologists in northern Iraq have conducted an extensive magnetic survey using an exhaustive magnetic survey at Khorsabad, once the ancient...

Polish researchers reveal what ancient Egyptian faience has to do with gold

31 December 2022

31 December 2022

Powdered quartz used to make faience vessels discovered by Polish archaeologists during excavations in the ancient city of Athribis in...

Researchers Finds Nearly 500 Ancient Ceremonial Sites in Southern Mexico with Lidar Technique

26 October 2021

26 October 2021

A team of international researchers led by the University of Arizona reported last year that they had uncovered the largest...

Three-Year-Old Discovers 3,800-Year-Old Canaanite Seal at Archaeological Site of Tel Azekah

2 April 2025

2 April 2025

At the site of the famous battle between David and Goliath, a three-year-old girl named Ziv Nitzan discovered a scarab-shaped...

Rare Roman Marble Sarcophagus Depicting Dionysus and Hercules Discovered in Caesarea, Israel — A First of Its Kind

9 June 2025

9 June 2025

A rare Roman-era marble sarcophagus featuring a vivid scene of a mythological drinking contest between Dionysus, the god of wine,...