Tomography

The mechanism seen by tomography

Original computed tomography slices of Fragment A, downloaded from the public Harvard Dataverse repository.

Computed tomography (CT) images the object with X-rays from thousands of angles and reconstructs its interior on a computer, layer by layer. This reveals the gears hidden inside the corroded bronze, without touching the fragment.

The images on this page are original slices of scan A6 of Fragment A, the largest. The data were gathered in Athens in 2005 by X-Tek Systems and are published on Harvard Dataverse (Antikythera Fragment A scan A6), together with the paper by Pakzad et al. in PLOS ONE (2018). They were downloaded from there and resized for the web; the text under each image states where it comes from.

The slices are parallel to the gears, one every 0.1 mm: 544 in all, from the front to the back of the fragment. Eight are shown here.

Slice 310 of the CT scan of Fragment A: The main wheel b1, with its four spokes and central hub.
slice 310 of 544
The main wheel b1, with its four spokes and central hub.
Slice 341 of the CT scan of Fragment A: At the centre of b1 the gear b2, with a smaller gear meshing with it.
slice 341 of 544
At the centre of b1 the gear b2, with a smaller gear meshing with it.
Slice 360 of the CT scan of Fragment A: Behind b1, more gears appear.
slice 360 of 544
Behind b1, more gears appear.
Slice 380 of the CT scan of Fragment A: Deeper: a large disc and smaller gears.
slice 380 of 544
Deeper: a large disc and smaller gears.
Slice 400 of the CT scan of Fragment A: A large, finely toothed wheel, with a small gear meshing with it.
slice 400 of 544
A large, finely toothed wheel, with a small gear meshing with it.
Slice 420 of the CT scan of Fragment A: The toothed rim of a large wheel and, on the right, smaller gears.
slice 420 of 544
The toothed rim of a large wheel and, on the right, smaller gears.
Slice 440 of the CT scan of Fragment A: Towards the back: the toothed arc of a large wheel and two smaller gears side by side.
slice 440 of 544
Towards the back: the toothed arc of a large wheel and two smaller gears side by side.
Slice 470 of the CT scan of Fragment A: The back of the fragment: a flat plate.
slice 470 of 544
The back of the fragment: a flat plate.

Credits

Data: Antikythera Fragment A scan A6, Harvard Dataverse, doi:10.7910/DVN/UCXZWU (deposited by Adam Gibson, UCL). X-ray Data courtesy X-Tek Systems (now owned by Nikon Metrology), 2005. Equipment loaned by X-Tek Systems Ltd (now owned by Nikon Metrology) was used to collect the data. The data are distributed under a Creative Commons Attribution (CC BY) licence.

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