Hijri Calendar 1440 | List of Hijri Months

Leap Years: In non-leap years, a month would be 29.5 days. Need to add 11 days in each 30-year cycle to account for a month being longer than that There are four different pattens of leap years in use for specifying which year in the cycle is a leap year.

These are designated as Type I, Type II, Type III, and Type IV

• Type I: 2, 5, 7, 10, 13, 15, 18, 21, 24, 26, 29
• Type II: 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, 29
• Type III: 2, 5, 8, 10, 13, 16, 19, 21, 24, 27, 29
• Type IV: 2, 5, 8, 11, 13, 16, 19, 21, 24, 26, 30

Origin

There are two different origins in use for 1 Muharram in the year 1. These are designated as the astronomical origin and the civil one

Astronomical Origin:

•   =1 Muharram year 1
•   = July 15, 622 (Julian Calendar)
•   = July 18, 622 (Gregorian Calendar)
•   = Ab 2, 4382 (Hebrew Calendar)

Civil Origin:

• =1 Muharram year 1
•   = July 16, 622 (Julian Calendar)
•   = July 19, 622 (Gregorian Calendar)
•   = Ab 3, 4382 (Hebrew Calendar)

Muslim Calendar Month versus Jewish Calendar Month That the Jewish Calendar and the Muslim Calendar have the months tied to the moon. So how do the lengths of a month in the two calendars compare?  You know that The Jewish month is defined to be 29 days, 12 hours, 793 halaqim. where a haliq  is 1/1080 of an hour

Based on that, the length of each year is dynamically adjusted so that the start of each year does not drift from the computed start of the first month in the year

The length of a Muslim month is computed as follows:

You know that A common year is 6 months of 30 days and 6 of 29 days for a total of 354 days

A leap year has an added day, and there are 11 leap years in every 30 year cycle, So 30 years = 354*30+11 = 10631 days, Since every year has 12 months, 30 years = 30*12 = 360 months. Therefore 360 months = 10631 days which means

•  1 month has  = 10631/360 days = 29 + 191/360 days
•  = 29 days + (191/360)*24 hours = 29 days + 191/15 hours
• = 29 days + 12  11/15 hours = 29 days + 12 hours + (11/15)*1080 halaqim
• = 29 days + 12 hours + 792 halaqim

AS a Result: The Jewish Month and the Muslim Month change by 1 haliq, or 3 1/3 seconds

Each month starts when the lunar crescent is first seen (by a human observer’s eye) after a new moon. So that new moons may be calculated quite precisely, the actual visibility of the crescent is much more difficult to predict. It depends on factors such as weather, the optical properties of the atmosphere, and the location of the observer.  Furthermore, some Muslims depend on a local sighting of the moon, whereas others depend on a sighting by authorities somewhere in the Muslim world.

So you can’t print an Islamic calendar in advance?

Not a reliable one. However, Hijri Calendar 1440  are printed for planning purposes, but such Hijri Calendar 1440  are based on estimates of the visibility of the lunar crescent, and the actual month may start a day earlier or later than predicted in the printed calendar.

Different methods for estimating the calendars are used.

Some sources mention a crude system in which all odd numbered months have 30 days and all even numbered months have 29 days with an extra day added to the last month in ‘leap years’  Leap years could then be years in which the number year mod 30 is one of the following: 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, or 29.

Such a calendar would give an average month length of 29.53056 days, which is quite close to the synodic month of 29.53059 days, so on the average it would be quite accurate, but in any given month it is still just a rough estimate. Better algorithms for estimating the visibility of the new moon have been devised.

 When will the Islamic calendar overtake the Gregorian calendar?

As the year in the Islamic calendar is about 11 days shorter than the year in the Christian calendar, the Islamic years are slowly gaining in on the Christian years. But it will be many years before the two coincide. The 1st day of the 5th month of C.E. 20874 in the Gregorian calendar will also be (approximately) the 1st day of the 5th month of AH 20874 of the Islamic calendar.

Doesn’t Saudi Arabia have special rules?

For civil purposes, Saudi Arabia doesn’t rely on a visual sighting of the crescent moon to fix the start of a new month. Instead they base their calendar on a calculated astronomical moon. Since 2002 (AH 1423) the rule has been as follows: If on the 29th day of an Islamic month,

• the geocentric conjunction (that is, the new moon as seen from the center of the earth) occurs before sunset, and
• The moon sets after the sun, Dear Student then the next day will be the first of a new month; otherwise the next day will be the last (30th) of the current month.