Talk at the Jewish Calendar Seminar on
Wednesday, 19 Marheshvan (Nov. 3), 4-5 pm

Speaker: Eng. Yaaqov Loewinger (Tel-Aviv)

Title:
"The 8th in the 19-year cycle of the Hebrew calendar:
another look at "Al ha-Sheminit""

Abstract:
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On Rosh ha-Shana 5765 we entered the 8th year of the 304th 19-year cycle
of the Hebrew calendar. It is well-known that the intercalation of this
year (and of some other years as well) poses some serious calendric
problems:  it seems this intercalation is not necessary in order to
achieve the main objective of the Hebrew calendar, namely to cause the
relevant days of Pesah 5765 to fall after the Vernal Equinox.

In the year 5746 (1986 CE), the 8th year of the previous cycle, we
investigated this problem in a special booklet called "Al ha-Sheminit". We
analyzed there also the essence of the intercalation rule of our calendar,
established its sources and drew conclusions regarding the possible date
of its establishment. We formulated there also the Basic Rule of the
Hebrew Calendar and its mathematical build-up. This enabled us to fix some
simple mathematical formulae for the necessary calendar calculations,
especially fitted for calculator and computer usage.

In our talk we will review the essence of the above booklet, and point to
some principles which were severely criticized by some important calendar
authorities, and need to be revised or at least re-formulated.