There is quite a bit of stir resulting from several books about “The Harbinger”. There is one flaw in the theory: the current calendar used in the calculations is moon-based, while there is no “Schmittah” in it. That, translated, is “land Sabbath” and it appears only in the ancient sun-based calendar, the one that at least 14 remnants of were found in the caves at Qumran.
The moon-based calendar only came into use in Israel when Solomon married one of the daughters of Hiram, king of Tyre. That was the same time he put the statue of the Chariot of the Sun – identical to the one over the Brandenburg gate – over the East Gate – the one that only the king could enter – that caused a near-revolt in the nation.
The moon-based calendar was devised and instituted in the first building of the city of Babylon by the queen-monarch at that time (her name is not conclusively established). It is important to note that at the time she instituted the moon-based calendar, the sun and moon were in synchronization at 30 days in each month. That changed later, so that the moon is now 11 days short of the sun-day count. Cultures that have maintained the moon-calendar unchanged find their year drifting backward to the point that it is useless for plowing, planting or breeding of animals.
It is also important to note that, as long as the temple stood, the holy days, required assemblies, were always figured by the sun calendar, the priestly cycles were planned in 24 courses with all commanded assemblies attended by all courses of priests, and a fixed year with fixed week-days within that year. In other words, the priests in the temple never set the holy days, including the Schmittah, or Land Sabbaths, by the moon calendar. The trumpets were sounded on the day prescribed by the sun calendar, the feasts were all called according to the sun calendar, everything done in the temple until the day it was destroyed was done by the sun calendar.
Why is it not in use today? Very simply because only a king can change the calendar. Hillel II set the rules for the moon calendar so it could be used until a king is anointed in Israel. For that to happen, the remnant of the 10 tribes of Northern Israel have to return, because the king will be from the tribe of Joseph, not Judah, a different story for a different day.