The Sanhedrin English The Sanhedrin English

Committee concerning the fixing of the Calendar

Examining witnesses during 2nd Temple times
A beit din reconstructs the receiving of eyewitness testimony
Rabbi Prof. Daniel Jackson giving evidence of the New Moon before a beit din in Jerusalem

A special court has been established to accept evidence concerning the sighting of the New Moon, as required by Jewish Law. This court is made up of various justices who are assembled to hear evidence as the opportunity permits. The purpose of the court is to increase awareness, develop skills, and resolve halachic issues that arise when determining the Jewish Calendar according to testimony by witnesses. At this point there is no intention to supercede the mathematical calendar currently in use and fix the calendar on the basis of the testimony, such a step should be unacceptable to the public and spiritual leadership. Nevertheless, witnesses appear before the court and are investigated with precision according to what they saw. Sometimes the witnesses may also bring photographic evidence to support their testimony. Evidence is already being collected by the yiresh shomaim volunteers throughout the Land of Israel, with the intention that testimony can be presented before the court in a full legal fashion when the peoples' hearts are ready for it.

Mathematical Calendar of Hillel II

It should be noted that the mathematical calendar of Hillel II has been in use since the year 4119 (359 CE), and it has functioned for approximately 1600 years without difficultly. However, in recent years, a situation has been created where more and more frequently the onset of spring does not coincide with calendar currently in use. This means that the calendar is beginning to drift noticeably. Albeit, the rate of drift is very slow, much slower than other lunar calendars (such as the Islamic calendar). However, if continued unchecked, we will be celebrating Pesach in the summer, rather than the spring. Our current calendar will exceed halachically acceptable limits and we will be celebrating Biblically commanded holidays at times other than when Scripture requires them to be celebrated. One could argue that if a change is necessary in any event, it would be most correct according to Biblical and Jewish Law to once again use the system of witnesses. But it is certain that we will not longer be permitted to use the mathematical calendar of Hillel II in the near future.


There is a requirement from the Torah (deOraisa) that Pesach come out two weeks after the first new moon of spring. The first day of spring according to the Solar Calendar is always March 21. The Jewish Calendar has a discrepancy of about one day every century. This means that by the year 6000, Pesach will come out two news moons (Sivan) after the first day of spring. The Natziv was one of the first poskim to bring up this question about a hundred and fifty years ago. Some poskim replied that Mashiach would come by the year 6000, so there was nothing to worry about. Others said this would become an halachic question that will eventually require the re-establishment of the Sanhedrin to universally authorize a change in the calendar.

Public Participation

Whoever sees the New Moon is invited to come to give their report at 8 Beer Sheva St., Jerusalem. Please call the court secretary Rabbi Amnon Hever Tel: 054-9400909 EMail: to confirm that you are coming.

Leading Justices

This committee is made up of various justices who are assembled to hear evidence as the opportunity permits. The justices are drawn from the list of Rabbonim with Semicha, but has not permanent members.

Legal Rulings & Opinions

Relationship to the Nascent Sanhedrin

The "Committee concerning the fixing of the Calendar" functions under the auspices of the nascent Sanhedrin.

It functions within the charter it has been given by the "Special Court for the Executive Oversight of the Sanhedrin". Views expressed by this committee, have not necessarily been reviewed by the nascent Sanhedrin.

The committee is expected to develop "expert legal opinions" and halachic "legal briefs" that may be used at a future date when the calendar may be determined by witnesses. The committee also hosts re-enactments of a beis din accepting testimony. Lastly it supports all efforts to develop scientific and logistics techniques to enable reporting of the new moon by witnesses in a timely and verifiably accurate fashion.

At this time, no change in the calendar is expressed or implied.

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