The Saros pointer slides at the hub end, as a pin in the end of the pointer follows the spiral groove between the scales (Freeth et al., 2006, Anastasiou et al., 2014). These indicate predictions of lunar and solar eclipses and sometimes both in that month. The predictions of eclipse possibilities are distributed around the four-turn spiral dial as glyphs in the month cells of the 223-month Saros scale. 2006) to gather high-resolution 3D X-ray data, revealing the internal features of the 82 surviving fragments of the Antikythera Mechanism. Another team from X-Tek Systems (UK) (now part of Nikon Metrology) carried out X-ray Computed Tomography (X-ray CT) (Hadland et al. A team from Hewlett-Packard (USA) used Polynomial Texture Mapping (PTM) (Malzbender and Gelb, 2006) (now commonly known as Reflectance Transformation Imaging) to examine the external surfaces of the fragments. Major research advances resulted from a data gathering operation (Freeth et al., 2006), carried out in 2005 by an Anglo-Greek team of researchers in collaboration with the National Archaeological Museum in Athens and two high-tech scientific companies. After more than a century of research, much of this highly complex mechanism is now understood (e.g., Price, 1975 Wright, 2002, Wright, 2005, Wright, 2006, Freeth et al., 2006 Freeth et al., 2008, Jones, 2017). This led to years of study and controversy as its true nature emerged. At the beginning, its significance was completely unrecognized-until it split apart some months later to reveal gearwheels, much to the astonishment of Museum staff. The Antikythera Mechanism was discovered by Greek sponge divers and taken to the National Archaeological Museum in Athens amongst a large array of ancient Greek artefacts. This revision is comprehensively refuted here, except for the identification of a new text character in one of the Index Letter Groups, which implies an interesting revision of the 2014 scheme but which preserves the elegant 2014 reconstruction of the back plate of the Antikythera Mechanism. The 2016 scheme implied a completely different picture of the whole of the back plate of the Antikythera Mechanism, destroying its essential mathematical symmetry. Later work in 2016 proposed a radical revision of this eclipse prediction scheme, though it did not challenge the mathematical basis of the scheme. The deeply puzzling grouping and ordering of these Index Letter Groups was solved with a simple mathematical model, which both explained these groups and the distribution of the glyphs round the Saros Dial-revealing an eclipse prediction scheme of extraordinary sophistication and ambition. The eclipse characteristics, such as the colour and magnitude of the eclipse, are listed together in the inscriptions, together with a group of Index Letters for the eclipses to which they apply. In that publication, the full eclipse prediction scheme was not understood but subsequent work in 2014 made substantial progress. The glyphs also include an alphabetical Index Letter, referring to inscriptions round the Saros Dial, which describe eclipse characteristics. A 2008 publication deciphered the meaning of the glyphs: they indicate whether the predicted eclipse is lunar or solar the possible visibility of the eclipse and its time of day. The eclipse prediction scheme is implemented through descriptive glyphs, inscribed round a 223-month Saros Dial at the rear of the Mechanism: a glyph in a particular month indicates a predicted eclipse. Understanding the complex eclipse prediction scheme on the Antikythera Mechanism has resulted from a fascinating series of discoveries. In 2005, it was established that it predicted eclipses, using a 7th century BC Babylonian eclipse cycle of 223 lunar months, known as the Saros Cycle. It was later shown to be a complex astronomical calculating machine and is now known as the Antikythera Mechanism. In 1901, an extraordinary ancient Greek artefact was discovered in a shipwreck just off the tiny island of Antikythera.
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