Among the numerous fragments of calendrical documents from Qumran, some, like this one from Cave 4, have distinctive features. Two special nights in every month of the lunar calendar of 354 days, which the wider community embraced, are listed in order, in a cycle of six years, that is, over seventy-two months: the night following that of the full moon in the middle of the month, when the moon begins to wane, and the night of the moon's total eclipse at the end of the month. While the first of these bears no specific designation, the other is denoted duqah or duqo(h), a term for the moon's thinness.
The dark, and therefore ominous, nights are dated by attaching them to days that precede them in the solar cycle of 364 days to which the Qumran community adhered. At the same time they are also synchronized with the concurrent days of the week of service in the Jerusalem Temple of a specific priestly watch.
It appears that these rosters, penned in a late Hasmonean or early Herodian bookhand, were intended to provide the members of the New Covenant with a timetable for abstaining from important activities on the days before the dark phases of the moon's waning and eclipse. In contrast, rabbinical tradition puts a premium on the moon's bright phases: the night of the new moon at the beginning of the month and the night of the full moon in its middle.
