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]
Image at right shows the far side of Moon:
Click on image to see a 150-second time-lapse movie of 13 lunar cycles.
Menu (click on desired choice):
- The Kalendis Calendar / Zmanim Calculator
( Free ) version 9.837(1547) released Jan 1, 2012 - Weekly Torah Portions and Special Sabbaths
- The Lengths of the Seasons
- The Duration of Twilight
- Rambam and the Seasons
- The Seasonal Drift of the Hebrew Calendar (correlation with solar cycle, long-term drift)
- Request for Rain (Sh'ela) and Blessing the Sun (Birchat haChamah)
- Why Divide Hours into 1080 Parts?
- Ancient Hebrew hourly mazalot (symbolic names) and weekday names
70KB
- Exact Hebrew Calendar Full Cycle Weekday Frequencies
- The Length of the Lunar Cycle
- 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
- The Rosh HaShanah Postponements
- 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.
- Applies the traditional Rosh HaShanah postponement rules to progressively shorter molad intervals.
- An Astronomical Hebrew Calendar
- Links to Geographic Name Servers (for User-Defined Locales in Kalendis)
- 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.
