The Hebrew Calendar

Bookmark or cite this page as <http://www.sym454.org/hebrew/>

by Dr. Irv Bromberg, University of Toronto, Canada

[Click here to go back to the Symmetry454 / Kalendis home page]

Menu (click on desired choice):

1. The Kalendis Calendar / Zmanim Calculator
   ( Free ) new version 9.735(1455)
2. Weekly Torah Portions and Special Sabbaths
3. The Lengths of the Seasons
4. The Duration of Twilight
5. Rambam and the Seasons
6. The Seasonal Drift of the Hebrew Calendar (correlation with solar cycle, long-term drift)
7. Request for Rain (Sh'ela) and Blessing the Sun (Birchat haChamah)
8. Why Divide Hours into 1080 Parts?
9. Ancient Hebrew hourly mazalot (symbolic names) and weekday names 14KB
10. The Length of the Lunar Cycle
11. Moon and the Molad
    • Correlation with lunar cycle, reference meridian, long-term drift
    • Novel fixed arithmetic cycle of "yerm eras" exactly equivalent to the traditional molad cycle
12. The Rosh HaShanah Postponements
13. The Rectified Hebrew Calendar (353-year leap cycle, progressive molad)
    • Fixed month lengths, obeys all weekday and day counting rules of the traditional Hebrew calendar.
    • Novel arithmetic adapts the traditional Rosh HaShanah postponement rules to progressively shorter molad intervals.
14. An Astronomical Hebrew Calendar
15. Links to Geographic Name Servers (for User-Defined Locales in Kalendis)
16. What's new at this web site?

Acknowledgement

I would like to thank my teacher and friend, Rabbi Moshe Ginz, who has helped this project progress by encouraging and by spending many hours reviewing the classical sources with me.