Days of week on Hebrew calendar the "four gates". Since three arrangements cannot occur within the fixed calendar, most holidays can each occur on one of four possible days. All the holy days and festivals fall in the months of Nisan through Tishrei, months one to seven. These months always have the same number of days, alternating 30 and 29. The next two months are Cheshvan and Kislev, months eight and nine. Both or either of these months can have either 29 or 30 days, allowing for adjustments to be made and the schedule in the coming year to be manipulated. (On a regular year, Cheshvan
Year Julian years is a way to precisely specify how many days (not how many "real" years), for long time intervals where stating the number of days would be unwieldy and unintuitive. By convention, the Julian year is used in the computation of the distance covered by a light-year. In the Unified Code for Units of Measure, the symbol, "a" (without subscript), always refers to the Julian year, "a", of exactly seconds. The SI multiplier prefixes may be applied to it to form "ka" (kiloannus), "Ma" (megaannus), etc. Each of these three years can be loosely called an "astronomical year". The