Rediscovering the star-map of Hipparchus

In Nature last month there was an extremely interesting article recording the discovery of a new text by Hipparchus in the palimpsest Codex Climaci Rescriptus, during – of all things! – a summer project led by Peter Williams of Tyndale Hall in Cambridge:

First known map of night sky found hidden in Medieval parchment – Fabled star catalogue by ancient Greek astronomer Hipparchus had been feared lost.

A medieval parchment from a monastery in Egypt has yielded a surprising treasure. Hidden beneath Christian texts, scholars have discovered what seems to be part of the long-lost star catalogue of the astronomer Hipparchus — believed to be the earliest known attempt to map the entire sky. …

 The extract is published online this week in the Journal for the History of Astronomy. Evans says it proves that Hipparchus, often considered the greatest astronomer of ancient Greece, really did map the heavens centuries before other known attempts. It also illuminates a crucial moment in the birth of science, when astronomers shifted from simply describing the patterns they saw in the sky to measuring and predicting them.

The manuscript came from the Greek Orthodox St Catherine’s Monastery in the Sinai Peninsula, Egypt, but most of its 146 leaves, or folios, are now owned by 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.

The older writing was thought to contain further Christian texts and, in 2012, biblical scholar Peter Williams at the University of Cambridge, UK, asked his students to study the pages as a summer project. One of them, Jamie Klair, unexpectedly spotted a passage in Greek often attributed to the astronomer Eratosthenes. In 2017, the pages were re-analysed using state-of-the-art multispectral imaging.

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. …

The article is long and interesting.  The formal publication is Gysembergh, V., Williams, P. J. & Zingg, E., “New evidence for Hipparchus’ Star Catalogue revealed by multispectral imaging”, J. Hist. Astron. 53, 383–393 (2022), and it actually seems to be online here.  From this:

Ὁ στέφανος ἐν τῷ βορείῳ ἡμισφαιρίῳ κείμενος κατὰ μῆκος μὲν ἐπέχει μ̊ θ̅ καὶ δ̅ ́ ἀπὸ τῆς α̅ μ̊ τοῦ σκορπίου ἕως ι̅ <καὶ> δ̅ ́ μ̊ τοῦ αὐτοῦ ζῳδίου. Κατὰ πλάτος δ᾽ ἐπέχει μ̊ ς̅ C καὶ δ̅ ́ ἀπὸ μ̅θ̅ μ̊ ἀπὸ τοῦ βορείου πόλου ἕως μ̊ ν̅ε̅ C καὶ δ̅ ́.
Προηγεῖται μὲν γὰρ ἐν αὐτῷ ὁ ἐχόμενος τοῦ λαμπροῦ ὡς πρὸς δύσιν ἐπέχων τοῦ σκορπίου τῆς α̅ μ̊ τὸ ἥμισυ. Ἔσχατος δὲ πρὸς ἀνατολὰς κεῖται ὁ δ′ ἐχόμενος ἐπ᾽ ἀνατολὰς τοῦ λαμπροῦ ἀστέρος [. . .] τοῦ βορείου πόλου μ̊ μ̅θ̅· νοτιώτατος δὲ ὁ γ′ ἀπὸ τοῦ λαμπροῦ πρὸς ἀνατολὰς ἀριθμούμενος ὃς ἀπέχει τοῦ πόλου μ̊ ν̅ε̅ C καὶ δ̅ ́.
Corona Borealis, lying in the northern hemisphere, in length spans 9°¼ from the first degree of Scorpius to 10°¼8 in the same zodiacal sign (i.e. in Scorpius). In breadth it spans 6°¾ from 49° from the North Pole to 55°¾.
Within it, the star (β CrB) to the West next to the bright one (α CrB) leads (i.e. is the first to rise), being at Scorpius 0.5°. The fourth9 star (ι CrB) to the East of the bright one (α CrB) is the last (i.e. to rise) [. . .]10 49° from the North Pole. Southernmost (δ CrB) is the third counting from the bright one (α CrB) towards the East, which is 55°¾ from the North Pole.

The technical details are of interest mainly to specialists.

The manuscript itself left Mount Sinai sometime in late 19th century, and ended up in the hands of the Cairo book dealers.  Agnes Lewis Smith, one of the “Sisters of Sinai” who discovered the Old Coptic Syriac gospels, was able to use her wealth and connections to purchase most of it between 1895-1906.  She left it to Westminster Hall, a theological college in Cambridge, where it snoozed away for a century.  But manuscripts have few long-term homes.  Indeed I recall that there was a minor scandal in 2010 when the college, pressed for money, decided to sell off the treasure at Sothebys for ready cash.

It seems that the book ended up in the hands of the American Steve Green, owner of Hobby Lobby, who was using his wealth, much as Agnes Lewis Smith had done, to retrieve valuable articles from the art trade.  He created a Museum of the Bible to house his collection, not without incredible vitriol from some papyrologists.  The purchase brought it into a quite different circle of scholars, with the results that we see.

It’s always a shame when an old collection is broken up.  Yet it is not always a bad thing.  Had the manuscript remained in Cambridge, would these contents still be unknown?  There is irony here, forTyndale Hall is also in Cambridge.  Yet the study could take place only once the manuscript had passed to the USA, and into the hands of a man wealthy enough to fund multi-spectral imaging, and inclined to do so.

Perhaps more collections need to be broken up?