Creator of the Symmetry454 CalendarWelcome ...

Created by Dr. Irv Bromberg, University of Toronto, Canada email icon

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Menu (click on desired choice):

  1. The Symmetry454 Calendar or the Symmetry010 Calendar
    • simple perpetual solar leap week calendars
    • conserve the traditional 7-day week
    • have symmetrical equal quarters
    • start every quarter on the same weekday (every month for Symmetry454)
    • symmetrically distribute leap years at intervals that are as smoothly spread as possible
  2. The Kalendis Calendar Calculator ( Free ) Version 11.157(1678) released Oct 8, 2020
  3. Mixed Radix Conversions (First published January 2022)
  4. Fixed Arithmetic Calendar Cycle Jitter
  5. Why March 21st?
  6. The Lengths of the Seasons
  7. The Length of the Lunar Cycle
  8. The Duration of Twilight
  9. Calendar Cycle Leap Rules
  10. The Traditional Hebrew Calendar and the Rectified Hebrew Calendar
  11. Small spreadsheet shows how to interconvert Year numbers with (Solar, Lunar, Indiction) cycle numbers
  12. Links to Geographic Name Servers (to set up User-Defined Locales in Kalendis)
  13. What's new at this web site?

Updated 8 Sivan 5782 (Traditional) = 8 Sivan 5782 (Rectified) = Jun 2, 2022 (Symmetry454) = Jun 4, 2022 (Symmetry010) = Jun 7, 2022 (Gregorian)