Astronomy and calendars at Qumran

A corpus of ca. 20 calendrical texts dated mostly to the first century BCE was found among the Dead Sea scrolls. These documents attest to a year of 364 days, which was adopted from earlier Jewish Pseudepigrapha like the Books of Enoch and Jubilees. The 364-day year was the main time frame used by the sectarian community represented in the scrolls. It is not a solar year, as often stated, but rather a schematic-sabbatical year. Its main characteristic in the DSS is the absorption of many various calendrical frameworks. The 364-day calendar tradition is strongly based on the calculation of full creational weeks and of weeks of years (Shemitah). It incorporates the service cycles of the 24 priestly families in the temple, while in addition, it encompasses an additional cycle of lunar phenomena. This cycle is related to the Mesopotamian concept of “the Lunar Three”.