Improved X-ray computed tomography reconstruction of the largest fragment of the Antikythera Mechanism, an ancient Greek astronomical calculator.

Ashkan Pakzad,Andrew Ramsey,Adam Gibson,Francesco Iacoviello,Tony Freeth,Robert Speller,Jennifer Griffiths,Mario Novak

doi:10.1371/journal.pone.0207430

Ashkan Pakzad, Andrew Ramsey + Show 6 more

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https://doi.org/10.1371/journal.pone.0207430

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Abstract

The Antikythera Mechanism is an extraordinarily complex ancient Greek astronomical calculating device whose mode of operation is now relatively well understood particularly since imaging studies in 2005 revealed gears and inscriptions which were previously illegible. Unfortunately, the highest resolution X-ray computed tomography image of the largest fragment had some errors which meant that the reconstructed images were not as clear as had been expected. Here, the original X-ray data have been reanalysed and reconstructed. The new X-ray computed tomography images have improved contrast and resolution, leading to better clarity and legibility. The improvement in image quality is characterised and some examples of writing on the Mechanism which can now be read with increased confidence are given.

Highlights

The Antikythera Mechanism is a 2000-year-old device which used at least 30 bronze gears to predict astronomical and social events including eclipses, phases of the moon, positions of the planets in the sky and even the dates of the Olympic and other games
Photographs and radiographs led to an improved understanding of the Mechanism [1,2,3] until a new set of high resolution reflectance transform imaging (RTI) and X-ray computed tomography (CT) images were acquired in 2005 [4]
The CT system used was made by X-Tek Systems Ltd (UK) ( Nikon Metrology): a BladeRunner with an experimental 450 kV micro-focus source, which was shipped from the UK to the National Archaeological Museum in Athens for the 2005 study [7]

Summary

Introduction

The Antikythera Mechanism is a 2000-year-old device which used at least 30 bronze gears to predict astronomical and social events including eclipses, phases of the moon, positions of the planets in the sky and even the dates of the Olympic and other games. It was recovered from a shipwreck in 1900–1 and consists of 82 corroded and calcified fragments. Photographs and radiographs led to an improved understanding of the Mechanism [1,2,3] until a new set of high resolution reflectance transform imaging (RTI) and X-ray computed tomography (CT) images were acquired in 2005 [4].

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Conclusion