 |
| 我的日历 |
| |
|
| 分类日志 |
| |
|
| 友情链接 |
|
|
| 最新评论 |
|
|
| 搜索日志 |
|
|
| 访问计数 |
|
|
| 获取 RSS |
| |
 | |
| |
太阴周期[Metonic Cycle] [2005-10-12]
iamet 发表在 ¤〖天文〗
| Meton of Athens (ca. 440 BC) noticed that 235 lunar months made up almost exactly 19 solar years. Using modern measurements,
  
The near commensurability of the two periods follows from the fact that 235/19 is the 6th convergent of the ratio of the lunar month and solar year periods (365.2425/29.53059).
This 19-year lunar cycle became known as the Metonic cycle, and was the basis for the Greek calendar until the Julian calendar was introduced in 46 BC. Since 12 lunar months equal 354.367 days, about 11 days less than a solar year, an additional  lunar months were added to synchronize the cycle. These were added in years 3, 5, 8, 11, 13, 16, and 19 of the cycle. The Metonic cycle was extended by Callippus to 4 19-year cycles, which is known as the Callipic cycle. |
学好数理化，走遍天下都不怕！ | |
|
|
