5 articles for "Meton / Metonic"

**Meton**[Astro*Index]

(mee'ton)

(BC440-?) Greek astronomer, born at Athens.

Known for his discovery, in BC432, that 235 lunar months was equal to 19 solar years.

**Metonic Cycle**[Astro*Index]

A 19-year coincidence cycle of lunar phase dates named after Meton, a Greek astronomer who in 433 BC. In 19-year intervals, new, quarter, and full moons repeat by day, sign, and degree. This phenomenon arises from the fact that a period of 235 lunations (6939.60 days) equals a period of l9 tropical years (6939.69 days). The Metonic cycle has interpretive signficance in terms of eclipses which occur at 19 year intervals in an individual's life, the so-called Metonic Return. Meton used this information to improve the accuracy of the lunar calendar in use at the time. The Greek calendar was in fact based on the Metonic cycle, and remained in common use until 46 BC, when Julius Caesar (with the help of Sosigenes) instituted the Julian calendar. Modern Jews still use the Greek calendar.

See also:

♦ Eclipse Year ♦ Embolismic Lunation ♦ Saros Cycle ♦ Greek Calendar ♦ Julian Calendar

**Metonic Cycle**[Munkasey M.]

An Eclipse cycle of exactly 19 years (measured date todate when eclipses occur in the same zodiacal longitude degree. Some 23"0' of the eclipses which occur do not follow this cycle. See also "Saros Cycle".

See also:

♦ Eclipse Year ♦ Embolismic Lunation ♦ Saros Cycle ♦ Greek Calendar ♦ Julian Calendar

**Metonic Cycle**[DeVore]

The discovery about 432 B.C. by Meton, an Athenian astronomer, of the Moon's period of 19 years, at the end of which the New Moon occurs on the same day of the year. Upon this he based certain corrections of the lunar calendar. He figured the 19-year cyclic of 235 lunations to consist of 6,939d, 16-5h. This he divided into 125 full months of 30 days each, and 110 deficient months of 29 days each. (*v. Lunar Month.*) the 235 full months, of 30 days each, totalled 7,050 days; hence it became necessary to suppress 110 days or 1 in 64. Therefore the month which contained the 64th day became a deficient month. As the true Lunation period is 6,939d, 14-5h, his calculations showed a deviation of only two hours.

The average date on which a Lunation will occur can be determined from the following table correlating Sun positions with the calendar:

METONIC CYCLE | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|

Golden | Capric | Aqua | Pisc | Aries | Taur | Gemin | Canc | Leo | Virgo | Libra | Scor | Sagit | Capric |

Number | 11°-30° | 1°-11° | |||||||||||

1 | 11 | 11 | 11 | 10 | 9 | 7 | 5 | 3 | 1-29 | 29 | 29 | 29 | 29 |

2 | 29 | 30 | 29 | 28 | 17 | 25 | 23 | 22 | 19 | 18 | 18 | 18 | 18 |

3 | 18 | 18 | 18 | 18 | 16 | 15 | 14 | 12 | 10 | 8 | 7 | 7 | 7 |

4 | 7 | 7 | 7 | 7 | 6 | 5 | 3 | 1-29 | 28 | 26 | 26 | 25 | 26 |

5 | 26 | 25 | 26 | 24 | 24 | 22 | 20 | 19 | 17 | 16 | 15 | 15 | 15 |

6 | 15 | 15 | 15 | 14 | 13 | 12 | 9 | 8 | 6 | 5 | 5 | 5 | 4 |

7 | 4 | 4 | 4 | 3 | 3 | 1-29 | 27 | 26 | 24 | 24 | 23 | 23 | 24 |

8 | 24 | 23 | 23 | 22 | 20 | 19 | 17 | 15 | 14 | 12 | 12 | 12 | 12 |

9 | 12 | 12 | 12 | 12 | 10 | 9 | 7 | 4 | 3 | 1 | 1 | 0 | 1 |

10 | 1 | 1 | 1 | 1 | 0-28 | 26 | 25 | 22 | 21 | 20 | 20 | 19 | 20 |

11 | 20 | 20 | 20 | 19 | 18 | 17 | 15 | 13 | 10 | 9 | 9 | 8 | 9 |

12 | 8 | 9 | 9 | 8 | 8 | 6 | 4 | 3 | 0-29 | 27 | 27 | 27 | 28 |

13 | 28 | 27 | 27 | 26 | 25 | 23 | 22 | 20 | 19 | 17 | 17 | 16 | 16 |

14 | 16 | 17 | 16 | 16 | 15 | 14 | 11 | 10 | 8 | 7 | 6 | 6 | 6 |

15 | 6 | 5 | 5 | 5 | 4 | 3 | 1-29 | 27 | 25 | 25 | 24 | 24 | 24 |

16 | 24 | 24 | 24 | 23 | 21 | 20 | 19 | 17 | 16 | 15 | 14 | 13 | 14 |

17 | 14 | 13 | 13 | 12 | 11 | 10 | 8 | 6 | 5 | 3 | 3 | 3 | 3 |

18 | 3 | 3 | 2 | 2 | 1-28 | 7 | 25 | 24 | 22 | 22 | 22 | 22 | 21 |

19 | 21 | 22 | 21 | 21 | 19 | 18 | 15 | 13 | 12 | 11 | 10 | 11 | 11 |

To ascertain the Golden number (q.v.) of any year, add 1 and divide by 19: the remainder is the Golden number. If there is no remainder, the number is 19.

See also:

♦ Lunar Month ♦ Eclipse Year ♦ Embolismic Lunation ♦ Saros Cycle ♦ Greek Calendar ♦ Julian Calendar

**Metonic Return**[DeVore]

Said of the recurrence of an eclipse on a given degree on the same date some 19 years later.

This should not be confused with the Saros Cycle (q.v.).

Astro*Index Copyright © 1997 Michael Erlewine

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