God, Hope & Helping Others
When the rabbinical Pharisees got control of regulating the calendar after 70 A.D., they replaced the original biblical calendar, based solely on observation, with a completely man-made calendar based on calculation. Their calendar is also based on an incorrect method of beginning the sacred year, which often allows the year to begin in March before an omer of barley would be ripe enough to harvest for the Wave Sheaf Offering. Incredible as it may sound, all of Christendom is using this rabbinical method of beginning the sacred year to calculate its observation of Easter.
Below is the URL to an article I wrote on the subject. You have to download a PDF file to read it.