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

Freeth T - PLoS ONE (2014)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Antikythera Mechanism Research Project, South Ealing, London, United Kingdom; Images First Ltd, South Ealing, London, United Kingdom.

ABSTRACT
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.

Show MeSH

Related in: MedlinePlus

Conjectural arrangement of back plate inscriptions.This uses the same colour conventions as described in the legend for Figure 9.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4116162&req=5

pone-0103275-g009: Conjectural arrangement of back plate inscriptions.This uses the same colour conventions as described in the legend for Figure 9.

Mentions: With no room round the Saros Dial, the only possible place for lunar eclipse inscriptions is round the Metonic Dial, where the plate has only survived for a few millimetres beyond the dial itself: so the direct evidence is lost. Figure 9 shows how they fit neatly here. The geometry of the spiral dials means that there is more room on the left of the Metonic Dial than on the right, so the reconstruction includes four Index Letter groups on the left and three on the right.


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

Freeth T - PLoS ONE (2014)

Conjectural arrangement of back plate inscriptions.This uses the same colour conventions as described in the legend for Figure 9.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4116162&req=5

pone-0103275-g009: Conjectural arrangement of back plate inscriptions.This uses the same colour conventions as described in the legend for Figure 9.
Mentions: With no room round the Saros Dial, the only possible place for lunar eclipse inscriptions is round the Metonic Dial, where the plate has only survived for a few millimetres beyond the dial itself: so the direct evidence is lost. Figure 9 shows how they fit neatly here. The geometry of the spiral dials means that there is more room on the left of the Metonic Dial than on the right, so the reconstruction includes four Index Letter groups on the left and three on the right.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Antikythera Mechanism Research Project, South Ealing, London, United Kingdom; Images First Ltd, South Ealing, London, United Kingdom.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus