The Creator's Calendar

Astronomical timings and lunar months computed by the The Creator's Calendar method

﴿ٱلشَّمۡسُ وَٱلۡقَمَرُ بِحُسۡبَانٖ ﴾ [الرحمن: 5]

“The sun and the moon follow a precise calculation.” [Ar-Rahman: 5]

About The Creator's Calendar

A natural astronomical calendar — not a conventional one — that reconstructs the temporal order the Creator established on the day the heavens and the earth were created, uniting the precision of the solar year (the seasons) with the true lunar cycle. It is the system that remained in use across the Arabian Peninsula until after the age of Prophethood, until it was replaced in the era of Muawiya by purely lunar reckoning.

What is The Creator's Calendar?

The Creator's Calendar is a lunisolar calendar: it draws its months from the natural lunar cycle, and anchors those months within the seasons of the solar year defined by the equinoxes and solstices. It does not sever time from its cosmic phenomena but matches them directly: the day by light, the month by the moon, and the year by the sun.

It thus differs from two common patterns: it is not purely lunar like the Hijri (lunar) calendar (whose months drift across the seasons), nor purely solar like the Gregorian calendar (which disregards the moon); rather it brings both references together, just as the sun and the moon come together in reckoning:

“The sun and the moon follow a precise reckoning.” [Ar-Rahman: 5]

The astronomical units and their rules

Day

Begins at the moment of true astronomical dawn (the sun 18° below the horizon), ends at sunset, and the night is appended to it for ordering.

Month

A natural lunar month born at conjunction (the dark moon); its first day is set by the moon-age rule, a precise computational substitute for sighting the crescent.

Year

A solar year of four seasons, bounded by the equinoxes and solstices — astronomical points tied to the limits of the sun’s motion between the tropics.

First: the day begins at dawn

The day is a cosmic unit that begins with the break of true dawn — that is, with the first spread of light on the horizon — not at midnight as convention has it in modern calendars. This is a precise astronomical moment, not an arbitrary one; indeed human life itself begins with the emergence of light.

Dawn Sunrise Noon Sunset Night (appended) — The day: from dawn to sunset —
The day begins at dawn and ends at sunset, with the night appended for ordering (see the “Units of Time” page).

Second: the month and when it begins

The month is tied to the moon; the new moon is born at the moment of conjunction with the sun, when its light vanishes. But the first day of the month is not counted from the moment of conjunction directly; rather the moon must reach an age sufficient to be seen if sought — a computational criterion that stands in for, and dispenses with, sighting the crescent. The rule:

If the conjunction occurs during the day
the first day is the next day
If the conjunction occurs at night
the first day is two days later

The moon and the sun together are the instruments of reckoning the Creator appointed for knowing the number of years and months:

“It is He who made the sun a radiance and the moon a light, and ordained for it phases, that you may know the number of years and the reckoning.” [Yunus: 5]

Third: the year and the four seasons

The year is solar, and its astronomical bounds are four points that cannot be ignored: the two equinoxes (spring and autumn) and the two solstices (summer and winter), tied to the limits of the sun’s apparent motion between the two principal latitudes (the tropics). As for designating a particular day as the “head of the year,” that is a conventional matter left to peoples and their cultures; the year has no “actual” astronomical beginning, only these four fixed points.

The Four Seasons Spring Summer Autumn Winter
The year is a cycle of four successive astronomical seasons, within which the lunar months are anchored.

Anchoring the months in their seasons (the linguistic evidence)

The month names themselves carry an explicit seasonal meaning — a linguistic basis showing that each month was tied to its season and did not drift away from it:

  • Rabi al-Awwal and Rabi al-Thani: “rabi” is Arabic for spring — they can only fall in spring, and upon them the rest of the months are ordered.
  • Jumada: from “jumud,” the hardening of grain in the ears as it ripens — the time of the harvest in summer.
  • Ramadan: from “al-ramad,” intense heat — the first fall of rain in autumn upon the hot ground.

Based on these meanings, twelve months are arranged within the four seasons:

SeasonThe months (in a common year)
SpringRabi al-AwwalRabi al-ThaniJumada al-Ula
SummerJumada al-AkhiraRajabShaban
AutumnRamadanShawwalDhu al-Qada
WinterDhu al-HijjaMuharramSafar

The rule for assigning a month to its season

Because the beginning of the “first day” may differ across regions of the earth, a decisive criterion was set for assigning a month to a season: the moon’s age must be two days at the moment the equinox or solstice occurs for that month to be counted within the season. (One day suffices in principle, but “two days” is a safeguard that absorbs the variation in determining the first day between regions of the world.)

Intercalation and Al-Nasi — an astronomical necessity

The solar year is ≈ 365.24 days, whereas twelve lunar months are ≈ 354.37 days, so a difference of about 11 days each year accumulates. Were this difference left unaddressed, the months would gradually drift away from their seasons (as happens in the purely lunar calendar).

Solar year ≈ 365.24 days 12 lunar months ≈ 354.37 days ≈ 11 days The difference accumulates yearly → a leap month (Al-Nasi) is added in a year with 13 new moons
Intercalation realigns the months with their seasons by adding a thirteenth month when needed.

When is a year a leap year? And where is Al-Nasi inserted?

  • The leap year: the year in which 13 dark moons (new moons) fall — so it needs an extra month.
  • The leap month (Al-Nasi): inserted into the season in which four moons of two-days’ age gather, restoring the balance of the months with the seasons.

The arrangement of months in leap years (with the position of Al-Nasi):

SeasonThe months (in a leap year)
SpringRabi al-AwwalRabi al-ThaniAl-NasiJumada al-Ula
SummerJumada al-AkhiraRajabShabanAl-Nasi
AutumnRamadanShawwalDhu al-QadaAl-Nasi
WinterDhu al-HijjaAl-NasiMuharramSafar

The historical origin (year one)

The starting point of the count (year one) is a purely historical matter; here it is a zero point inferred by calibration against the agreement of the events narrated in the sources with it. By this calibration, the first day of the calendar is as follows:

First day (01-01-0001 of The Creator's Calendar)corresponds to
Gregorian09-02-0623
Julian06-02-0623
Solar Hijri19-11-0001
Hijri (Lunar)01-08-0001

That is, the first year — according to Madinah — corresponds to the year 623 CE.

The historical evidence: the agreement of events

The central practical argument for The Creator's Calendar is that it is the only calendar with which the events dated in the Arabic sources agree to a high degree.

The events occurring from the birth of the Prophet (peace be upon him) to al-Hasan’s handover of rule to Muawiya agree with The Creator's Calendar and do not agree with purely lunar reckoning. The events following Muawiya’s rule, however, agree with the Hijri (lunar) calendar. From this shift at a specific historical juncture it is inferred that the original system was replaced at that point.

This agreement can be traced event by event, with its historical sources, on the Events page:

Sources and the basis of calculation

Historical sources

  • Al-Maghazi — by Muhammad ibn Umar al-Waqidi.
  • Tarikh al-Rusul wa al-Muluk (History of the Prophets and Kings) — by Muhammad ibn Jarir al-Tabari.
  • The detailed sources are cited with each event on the Events page.

The basis of astronomical calculation

The moments of conjunction, the equinoxes and solstices, and the times of dawn and sunset are computed with high precision, relying on astronomical ephemeris data from NASA’s Jet Propulsion Laboratory (NASA/JPL) and Meeus’s algorithms for the moon’s phases — enabling precise instantaneous calculation for any geographic location.

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