|
|
|
|
|
|
|
these Tekufoth have migrated from their original positions in the calendar and continue to do so. In the present century, the dates are 17 days later than their actual astronomical counterparts. |
|
|
|
|
|
|
|
|
9.4.1.1.9
Additional Cycles |
|
|
|
|
|
|
|
|
The calendar contains four cycles (Mahzorim), which may be ignored from the standpoint of calendric structure, since they relate to religious observance. These are: |
|
|
|
|
|
|
|
|
The Small Mahzor, a lunar cycle of 19 years. A period of 13 cycles is an Iggul. |
|
|
|
|
|
|
|
|
The Great Mahzor, a solar cycle of 28 years. |
|
|
|
|
|
|
|
|
The Yobel (Jubilee) cycle, a cycle of 50 years. The 15th and 65th years in each century of the Anno Mundi era are Yobel years. This cycle and the next are related to the destruction of the second Temple. |
|
|
|
|
|
|
|
|
The Shemittah (release) cycle of 7 years. The 49 years between the Yobel years are arranged as seven cycles of release years. Each year evenly divisible by seven is a Shemittah year. |
|
|
|
|
|
|
|
|
The Jewish calendar is not internally stable, in terms of its own logic. The religious mandate to maintain a correct solar year length is not, technically, being implemented, with the consequence that the calendar is slowly drifting out of synchronization with the actual solar tropical year. |
|
|
|
|
|
|
|
|
The reason for this is apparent upon examination of the length of the solar year implemented by the calendar, compared to the actual length of the tropical solar year: |
|
|
|
|
| Days | Hours | Minutes | Seconds | | Jewish: | | | | | | Actual: | | | | |
|
|
|
|
|
|
The error is equivalent to approximately four and one-half days every 1,000 years. Given the length of time over which the Jewish calendar has been in operation, this error has accumulated to a sizable period. In the year A.M. 5708, for example, Nisan 15 (Pesach) occurred on the Gregorian date of 24 April 1948, more than a full month after the vernal equinox. |
|
|
|
|
|
|
|
|
The corresponding situation with regard to the moon is better. The reason for this is apparent upon examination of the length of the average month implemented by the calendar compared to the actual length of the average synodic month. |
|
|
|
|
| Days | Hours | Minutes | Seconds | | Jewish: | | | | | | Actual: | | | | |
|
|
|