Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.

The ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, ref...

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Main Author: Tony Freeth
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4116162?pdf=render
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spelling doaj-a71560da9de040549073eb85878f2ef92020-11-25T02:31:29ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0197e10327510.1371/journal.pone.0103275Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.Tony FreethThe ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions. These include Index Letter Groups, describing shared eclipse characteristics. The grouping and ordering of the index letters, the organization of the inscriptions and the eclipse times have previously been unsolved. A new reading and interpretation of data from the back plate of the Antikythera Mechanism, including the glyphs, the index letters and the eclipse inscriptions, has resulted in substantial changes to previously published work. Based on these new readings, two arithmetical models are presented here that explain the complete eclipse prediction scheme. The first model solves the glyph distribution, the grouping and anomalous ordering of the index letters and the structure of the inscriptions. It also implies the existence of lost lunar eclipse inscriptions. The second model closely matches the glyph times and explains the four-turn spiral of the Saros Dial. Together, these models imply a surprisingly early epoch for the Antikythera Mechanism. The ancient Greeks built a machine that can predict, for many years ahead, not only eclipses but also a remarkable array of their characteristics, such as directions of obscuration, magnitude, colour, angular diameter of the Moon, relationship with the Moon's node and eclipse time. It was not entirely accurate, but it was an astonishing achievement for its era.http://europepmc.org/articles/PMC4116162?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Tony Freeth
spellingShingle Tony Freeth
Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.
PLoS ONE
author_facet Tony Freeth
author_sort Tony Freeth
title Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.
title_short Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.
title_full Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.
title_fullStr Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.
title_full_unstemmed Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.
title_sort eclipse prediction on the ancient greek astronomical calculating machine known as the antikythera mechanism.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2014-01-01
description The ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions. These include Index Letter Groups, describing shared eclipse characteristics. The grouping and ordering of the index letters, the organization of the inscriptions and the eclipse times have previously been unsolved. A new reading and interpretation of data from the back plate of the Antikythera Mechanism, including the glyphs, the index letters and the eclipse inscriptions, has resulted in substantial changes to previously published work. Based on these new readings, two arithmetical models are presented here that explain the complete eclipse prediction scheme. The first model solves the glyph distribution, the grouping and anomalous ordering of the index letters and the structure of the inscriptions. It also implies the existence of lost lunar eclipse inscriptions. The second model closely matches the glyph times and explains the four-turn spiral of the Saros Dial. Together, these models imply a surprisingly early epoch for the Antikythera Mechanism. The ancient Greeks built a machine that can predict, for many years ahead, not only eclipses but also a remarkable array of their characteristics, such as directions of obscuration, magnitude, colour, angular diameter of the Moon, relationship with the Moon's node and eclipse time. It was not entirely accurate, but it was an astonishing achievement for its era.
url http://europepmc.org/articles/PMC4116162?pdf=render
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