A simple, accurate, solar calender for Earth
Hi, and welcome to the Earthian Calendar, designed and published in 2008 (Common Era). This calendar is exceptionally straightforward and easy to use, easy to adopt, and offers a range of improvements over other Earth calendars in use.
The primary improvements are as follows:
- The year begins on the northern vernal equinox, thus months are closely aligned with seasons.
- Month lengths follow a simple alternating pattern of 30, 31, 30, 31...
- There is only one leap year rule.
This section provides a no-frills explanation of the calendar, just enough information to define it. If you would like to learn more about the design, convert dates, or create a printable version, please use the menu to the right.
- The year begins on the northern vernal equinox, following the convention in astronomy and astrology. Months are therefore aligned with seasons.
- Like other solar calendars, calendar years are either 365 days (common years) or 366 days (leap years) in length.
- Leap years are determined by one simple rule: It's a leap year if year mod 33 mod 4 = 2 (See: Modulo Operator Explained). Thus, in every sequence of 33 years there are 8 leap years, in the symmetrical pattern 001000100010001000100010001000100. This rule gives an average calendar year length of 365.2424 days, equal to the average length of the vernal equinox year. A period of 33 years is referred to as a generation.
- The first day of the calendar (1 Aries 0000, or 0000/01/01) equals 21 March 2007 (2007-03-21) in the Gregorian Calendar. This date was chosen because:
- This is very close to the current year, and
- The NVE occured at almost exactly midnight (00:09) on that date.
- Years before the year 1 are numbered 0, -1, -2... etc., like ordinary integers, following the convention in astronomy.
- The year is divided evenly into 12 months.
- Months are named after the 12 traditional zodiacal constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces. The standard 3-letter abbreviations for the constellations are used as abbreviations for the month names.
- Month lengths follow an alternating pattern of 30 and 31 days. Pisces has 30 days in common years, and 31 in leap years.
# Name Abbrev. Length Northern Season Southern Season 1 Aries Ari 30 Spring Autumn/Fall 2 Taurus Tau 31 3 Gemini Gem 30 4 Cancer Cnc 31 Summer Winter 5 Leo Leo 30 6 Virgo Vir 31 7 Libra Lib 30 Autumn/Fall Spring 8 Scorpius Sco 31 9 Sagittarius Sgr 30 10 Capricornus Cap 31 Winter Summer 11 Aquarius Aqr 30 12 Pisces Psc 30/31
- Weeks have 7 days, as usual.
- The days of the week are named after the 7 Solar System bodies visible to the naked eye: Sunday, Lunaday, Marsday, Mercuryday, Jupiterday, Venusday and Saturnday.
- The first day of the week is Sunday. The days of the week are number from 1-7, with Sunday being 1 and Saturnday being 7.
- Weeks within a year are numbered from 1 to 52 or 53. For weeks on year boundaries, the week belongs to the year that contains 4 or more of its days.
- Dates are written as YYYY/MM/DD, with month and day padded with an extra 0 if necessary to make 2 digits, and years padded to 4 digits. For example: 0001/02/25 (today), or -0036/08/10 (my birthday). The date can optionally be followed by "GE" for "Golden Era" (c.f. "CE" for "Common Era"). There is no abbreviation "BGE" for "Before Golden Era"; a minus sign is used instead.