Ancient Greek astronomer Hipparchus worked to accurately catalog and record the coordinates of celestial objects. But while Hipparchus’ Star Catalogue is known to have existed, the document itself is lost to history. Even so, new evidence has come to light thanks to patient work and multispectral imaging.
Hipparchus’ Star Catalogue is the earliest known attempt to record the positions of celestial bodies (predating Claudius Ptolemy’s work in the second century, which scholars believe was probably substantially based on Hipparchus) but direct evidence of the document is slim.
That is somewhat less true after it was discovered that the coordinates of Corona Borealis (the Northern Crown) appeared to be hidden within some ancient documents. This led to further investigations, which yielded a translated passage, some of the strongest evidence yet of Hipparchus’ lost work. It describes the Corona Borealis and gives coordinates accurate within one degree; considerably more precise than Ptolemy’s calculations. A remarkable achievement for a second-century scholar, considering that the telescope would not be invented for another 1500 years or so.
How was this information uncovered? Multispectral imaging of a palimpsest manuscript (a parchment erased of writing, then re-used) revealed the earlier markings, followed by reconstruction and translation. In 2012 an undergraduate student named Jamie Klair first noticed the astronomical nature of of the undertext present in some pages of the ancient Greek palimpsest known as the Codex Climaci Rescriptus. Peter Williams, a biblical scholar at Cambridge University, later noticed it contained the astronomical measurements of the Corona Borealis in 2021, which led to the discoveries.
Hipparchus’ Star Catalogue is far from having been rediscovered, but this is the most direct evidence yet of an important piece of science history from the ancient Greeks; much like the marvelous device known as the Antikythera mechanism.