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Adopting Dates






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Muslims Must Adopt Calculated Islamic Hijri Dates

Omar Afzal Ph.D. (1986, Revised 1998)


The Islamic month always started from the sunset after a crescent moon was sighted on the 29th or 30th day. The crescent moon’s universal visibility was easy especially in dry climates. Though the “New Moon” calculation was known for centuries a Hilal’s visibility computation remained elusive. For centuries Muslim astronomers tried to improved on various criteria that predicted the earliest visibility of the crescent moon but were not successful. (See Moon’s Earliest Visibility Criteria).

Abdali (1978) suggested a criterion that could calculate the probability of the ‘local’ sighting quite accurately for a broad region. Ilyas suggested tri-zonal and bi-zonal visibility solutions. However, a Hijri calendar, like any usable calendar cannot have two or more first dates of an Islamic month.

 Afzal (1986:IIT Lunar Calendar Conference) suggested that a global lunar Hijri calendar was possible to calculate if:

1)      180E (International dateline) is also adopted as the International lunar dateline

 (ILDL), and

2)      the beginning of the Hijri month is calculated when the moon’s earliest visibility occurs close to  ILDL after the sunset.

A calculated global Hijri calendar has several advantages. It conforms with the Qur’an (2:189), the Sunnah, and the Islamic tradition (Ru’yah); has uniform fixed dates of Islamic occasions (Ramadan, Eidain and Hajj) for the entire globe; allows use of Islamic dates for civil purposes, and makes easy conversion to future solar dates possible.

If the calculations for the crescent moon’s earliest visibility are so accurate, and easy, then why do the Muslims not adopt it?  The answer lies in our ignorance and ego. 

1.      Saudi/Egyptian calendar makers insist on their “Moonset after the sunset” criterion to calculate the Islamic dates by the New Moon;

2.      Many groups around the world insist on following Saudi/Egyptian dates;

3.      Muslim astronomical experts are split about what is the minimum threshold of moon’s local visibility and how to fix the date for a region (Sharing the night);

4.      Muslim moon-watchers are on a mad chase of the “earliest visibility of the crescent”, often contradicting all known visibility limits, and making claims that could not be verified from places located west of the earliest visibility;

5.      Muslim experts attest spurious claims by throwing all known norms out of the window;

6.      Local Imams succumb to the pressure of their congregations, or by calls for “unity”.

7.      According to some, the Messenger (S) asked the Muslims not to rely on calculation for the crescent (the ‘Ummiya’ Hadith.

(In N. America, ISNA Fiqh Council consists mainly of Imams who have to lead their respective congregations on the dates announced by S. Arabia/Egypt, irrespective of whether the crescent moon’s visibility could be ascertained.  Warith Deen’s group goes strictly by his fixed dates. ICNA worries about unity of dates with ISNA FC. Local Imams are forced by congregations to follow the decision by national organizations.)


Calculated Islamic dates in early Muslim History

If the Islamic month starts from the sighted moon after the sunset on the 29th or 30th day and the calculations predicting the crescent moon (Hilal) observation are fairly accurate, then why have the Muslims not adopted it?


The answer is:

1) Because, according to some Ulema, the Messenger (S) asked the Muslims not to rely on calculation (Hisaab) for the crescent (the ‘Ummiya’ Hadith), and

2) for others, Saudi or Egyptian calculations are more reliable.         

It is not true that the Muslim Ummah was unanimous in rejecting the “Hiasaab” (calculations) to determine the beginning of an Islamic month despite the fact that the calculations for “Hilal” (the earliest visible crescent moon) were far from accurate in their age.

Prominent Tabi’in like Mutraf b. Abdullah, Muhadditheen like Ibn Qutaiba, Fuqaha like 

Imam Shafi’i, Ibn Suraij, Ibn Daqiq al-Eid, Daudi and others had permitted the use of calculations for determining the Ramadan and Eidain dates. Imam Abu Hanifa is quoted in Qaniyah as saying: “There is no harm in depending on the words of the astronomers  (for determining the month).” Ibn Muqatil went a step further. He says that there is nothing wrong in depending on the words of the astronomers, and asking them about the dates if a group of them agrees on the same.

The Muslim astronomer like Al-Biruni improved on the calculations for the crescent observation. However, they were unable to explain why a crescent is not always visible on a day predicted by their rules for a moon’s visibility. The Ulema, for their fear of ‘the new and the unknown’, continued to insist on ‘shahaada’ though it created far more confusion everywhere than the ‘words of the Munajjim’.

Among the later Fuqaha, Subki, Shakir, etc. strongly supported the need for using calculations to judge  the accuracy of ‘Shahaada’ and avoid blunders. In recent years Ulema like Qaradawi go to the extreme of discarding ‘ru'yah’  for the calculated New Moon.                                      

Ummiyah Hadith.

Before refuting the “Ummiyah” argument let us understand the background of this Hadith.                        

During the time of the Messenger (S) the Arabs followed tribal lunar calendars with some form of ‘Nasi’ (adding a month every three years to keep pace with the solar seasons). When he (S) reached Medina he found the Jewish tribes following their fixed luni-solar calendar.  Circumstantial evidence shows that the Messenger (S) fasted the first ‘Ashura’ according to the Jewish calendar (Bukhari:  The Messenger (S) saw the Jews of Medina fasting the day of Ashura. He asked (them): What is it (that you are celebrating)? They said: It is a good day - the day Banu Israel were emancipated from their enemy (Fir’awn). Musa (A) fasted this day. He said: I am more rightful of Musa than you. He (S) then fasted himself and asked other (Muslims) to fast. (Sahih Muslim and others also have similar versions) 

The Jews, like the Hindus, Babylonians, and the Chinese were aware of the lunar calculations. The Jewish calendar committee used to check the accuracy of moon-sighting claims by their calculations of the conjunction at Jerusalem. As Spier (1988:p.2) mentions:

“In the 4th century C.E. ... the patriarch Hillel II took an extraordinary step to preserve the unity of Israel. In order to prevent the Jews scattered all over the surface of the earth from celebrating their new Moons, festivals, and holidays at different times he made public the system of calendar calculation which was upto then a closely guarded secret.... In accordance with this system, Hillel formally sanctified all months in advance, and intercalated all future leap years until such time as a new Sanhedrin would be established in Israel. This is the permanent calendar according to which the New Moons and festivals are calculated and celebrated today by the Jews all over the world.

The Jews in Medina used the same fixed calendar calculated by the New Moon in Jerusalem, whereas the Arab tribes made their local calendars based on a visible crescent moon. The Muslims in Medina continued to follow the sighted crescent moon. In the coming years, the Jews became hostile to the Messenger (S) and belittled him for lacking such basic “knowledge” that was commonly known to their Rabbis for centuries. Whenever the Muslims were unable to see a crescent moon because of clouds or dust as was the customary Arab method to start the month, the Jews slighted them by telling that the new month had already started a day or two ago (Tabari:2:189).

The Messenger (S) had two choices: 1) Ask the Muslims to follow the Jewish calendar, thus making them completely dependent on the Jewish Rabbis for Ramadan, and Eidain dates, or 2) Ask them to follow the customary obvious sign in the sky: a crescent moon which was always visible on the 29th or 30th day. Later, the Qur’an abolished ‘Nasi’ and asked the Muslims to follow the ‘Hilal’ (a crescent) to count all their 12 months, and for determining the Hajj dates.                                                         

The Ummiya Hadith was not a standing command to the Muslim Ummah to remain ‘Ummi’ for all the time to come till the end of time. It was never meant to be a permanent injunction against the calculations, as some Ulema have tried to argue in recent days.

How could the Messenger (S) forbid what the Qur’an itself confirms? The Quran specifically mentions that the sun and the moon are on a computed course (55:5). Allah used ‘Hisab’ and its derivatives in the context of the moon in several Ayahs and mentions fixed ‘Manazil’ of the moon. However, as the Muslims did not know the lunar calculations like the Jews and Hindus, the Messenger (S) asked them to rely on the Hilal (a visible crescent). In case the horizon was cloudy on the 29th day then wait another day to complete 30 days of the lunar month, because a crescent moon is always visible on 30th day.

Another prevailing misconception among the Muslims is that they can stop fasting if they have completed 30 days of fasting, even if the Shawwal crescent is not visible on a clear horizon. They quote the same 29/30 days long month Hadith as their argument (For details see the books of Fiqh).

The Hadith must be taken for its obvious meaning: The lunar month is either 29 or 30 days long. Muslim must try to see a crescent moon on the 29th evening. If it is not seen then they will certainly see it on the 30th evening.

The Messenger (S) made it very clear that the fasting has to begin by  ‘ru'yah’(sighting), and end only  after  ‘ru'yah’, except if the ‘matla’ is cloudy or dusty. In case the clouds and dust block the visibility then complete the month 30 days. It is a fact that a crescent will always be visible on the 30th day.

Eyewitnesses (Shahaada)                                                                                                 

At present a major source of confusion about Ramadan and Eidain dates are eye-witnesses, and the news from certain Muslim countries. For example, in 1994, the Muslims in N. America celebrated Eid on 3 different days. A small group had Eid on Sat. Mar. 12 because 3 Muslims claimed seeing a Shawwal crescent on Friday. Most of the Muslims had Eid on Sunday, Mar. 13 because 2 out of 3 in Los Angeles and 3 in Lodi, CA claimed a sighting. All claims were rejected after careful evaluation by the experts. But arguments were twisted for a Sunday Eid. The experts told the decision-makers that Eid on Sunday might make Shawwal 31 days. All were unanimous that Shawwal crescent cannot be seen on Sat. Mar. 12, 94.

As predicted by the experts, the D. Qada crescent was not seen in L.A. on Apr. 11, and Shawwal became 31 and 32 days. Similarly, in 1993 the Muslims started Ramadan on 3 days and celebrated Eid al-Fitr on 4 dates. Saudi Majlis al-Qada-A’la confirmed moonsighting (?) on Feb. 21, 93 (Sunday). Some groups in NWP in Pakistan and Afghanistan, some Islamic centers in Europe, and the Islamic Center Washington DC decided to accept the news of sighting and started Ramadan on Monday.  Indonesia, Malaysia, Iran, Turkey, Algeria, Morocco, etc. started on Tuesday although a sighting was impossible in Indonesia, and Malaysia.  Bangladesh, India and Pakistan started on Wednesday after seeing a crescent on Tuesday. S. Arabia and some Gulf sheikhdoms celebrated Eid al-Fitr on Tuesday, Mar. 23, 1993. Oman, Yemen, Egypt, Morocco, etc. confirmed non-sighting on Monday but celebrated Eid on Wednesday. From Indonesia to Turkey it was celebrated on Thursday, and in  S. Africa, etc. on Friday.  The Muslim communities in the US and Europe followed the news of their choice, though the sighting was possible only on Wednesday. Which one of these dates was correct?                                                                

Often it is argued that we should close our eyes and accept every ‘shahaada’. How can we reject a claim of moon-sighting by a Muslim when the Messenger (SAW) accepted it from an ‘A’raabi’? 


There are several arguments to counter this hypothesis:                                                             

a)      There is nothing in the Quran and the Sunnah that compels us to accept false witnesses. The Quran forbids us from acting on the false news.                                                                                                  

b)      The Messenger (S) accepted the A’raabi’s account because: 

1. There was no counter- evidence to prove that his claim was false.

2. The Messenger (S) wanted the Muslims to begin Ramadan, but they were reluctant.

3. The Jewish lunar date was supporting his claim.

4. The A’raabi was one of the uncles of Hadrat Anas (RA).

5. The Messenger (S) questioned the A’raabi’s claim.

6. The Messenger (S) was deciding Ramadan for a town, not a whole country, a continent or the whole world.


c)      Later, The Khulafa and the Companions rejected the news of sighting from other places if the crescent was not clearly seen in their town on a clear horizon.
d)      Earlier Fuqaha argued for the minimum number of witnesses from a town. When false claims by eye-witnesses increased dramatically Imam Abu Yusuf, as the Qadi of Bughdad required at least 50 witnesses.   Later, he required ‘a group from every mosque’ in Baghdad. Khalaf b. Ayyub required a minimum of 150, and the Qadi in Bukhara wanted a number as large as 1500.                                                                                 

Every individual or committee which has been assigned the task of evaluating the eye-witnesses anywhere in the world will confirm that the Muslims claim the most odd and utterly unbelievable sightings at all times and in every direction. There is a very simple rule:



If not, then the claim is FALSE. ‘Official’ eye-witnesses supporting a political decision on Eidain and Ramadan dates can easily be proven false and rejected on the following grounds:           

1. Shahaada is ‘Zann’.

2. Moon’s calculations are ‘Yaqeen’. They are accurate to the hundredth of a second.

3. Non-sighting in the same area, and areas west of it are ‘yaqeen’. Yaqeen’
        always takes precedence over ’zann’.                 


Ikhtilaf-i Matali’                                                      


Many Ulema brush aside all arguments because for them it is a matter of following a Fiqh position.  You believe in Ikhtilaf-i Matali’, and I believe in the whole world being one Matla’. Because of the discovery of the  ‘Visibility Separator Curve’ the whole discussion of Matali’ is now irrelevant.  The world is a globe, not a flat field, and the crescent’s viability extends westward in a parabola. Those who insist on Wahdat-i Matla’ are wrong because the crescent does not become visible instantly all over the world. It takes 24 hours like the sun (or more) to be seen all over the globe. It is wrong that ‘Ikhtilaf-i Matali’ means every town would see a crescent on different dates.                                     


Often we worry about celebrating Eid on two days because we forget that an Islamic day/date begins after sunset and a solar day/date begins at midnight. Then there is the International Dateline. Two islands only 100 yards apart will have two different dates if the IDL is passing between them. There is no International Lunar Date Line (ILDL) because the crescent becomes visible at a different place every month, and the cycle is not repeated in centuries. If we decide that all the Muslims should celebrate on the same solar date then we have to decide what to do with the Qur’an and the Sunnah. If we decide to strictly abide by the lunar date then the Muslims will always celebrate their Eids on two solar dates. If we ask all the Muslims to accept the first visibility instantly then we face several problems. What about the countries where a crescent was not and could never be seen that evening? How far east, north/south- east will we extend the lunar date on a globe? In some countries the sun may be coming out, and in others it would be mid-day. How will the Islamic day / dates be fixed?                                              

As a matter of fact, the whole world is one Matla’, but in a 24 hours long Islamic day/date which will always be two solar dates. We have to agree on certain traditions to accommodate the geophysical realities.                                                                                                                                         

Astronomers differ


Often the Ulema argue that how can they accept ‘calculations’ when the astronomers themselves do not agree among themselves? The calculations do not differ. All astronomers will come up with the same answer if they are asked to calculate the conjunction (New Moon), and the moon’s position on a certain date. Where they differ is: When the Moon will be visible as a crescent?   Even this disagreement has narrowed down in the last decade. They agree that the Moon CANNOT BE SEEN before the New Moon phase, that the Moon CANNOT BE SEEN immediately after the New Moon’s birth, that there is a zone of improbable visibility. They disagree only where will it be seen the earliest, as discussed earlier.  When will the crescent be certainly visible? is a question which we are facing for the last 3,000 years. The Committee for Crescent Observation has come to the conclusion that as a rule of thumb the crescent will be visible at every location where its angle is 12+ degrees and the altitude exceeds 10 degrees at sunset. In some rare cases, a crescent may be seen a little early by expert observers through binoculars and telescopes, but not very far off.


29 / 30 Days         


For years Saudi Arabian authorities have used the 29/30 days Hadith to justify some of their dates. Obviously, 30 days must be counted from the last crescent, not from the Conjunction (New Moon). The Moon will always be visible on the 30th day in Saudi Arabia. It is extremely unlikely that the whole kingdom would be cloudy after the sunset. If a crescent is not visible on a clear horizon then it is certainly not the 30th day. It is self-contradictory to claim that ‘30 days are complete but the crescent was not seen anywhere in the kingdom’.      



News From Anywhere                                     


We have mentioned that the lunar visibility is within a parabola. The crescent will be certainly visible within the visibility parabola. The news coming from within the visibility curve is useless for the areas outside the curve.  A crescent cannot be seen there. They should continue their month for another day. The news is useful only for those areas within the curve where the crescent’s visibility is blocked by clouds or haze.                                   


The Qur’an confirms the accuracy of the calculations for the rotation of the sun and the moon (55:5). However, in the early period of the Islamic history those calculations were not known to the Muslim Ummah. The Messenger (SAW) asked the Muslims to depend on their eyes, and use the simple count of the days of the month. If the crescent is not visible on the 29th, then it will certainly be visible on the 30th day.


The Jews in Medina used their lunar calendar for determining the beginning of their lunar month. It was usually a day or two ahead of the visible crescent. Their computation was fairly accurate, but the Messenger (SAW) did not want the Muslims to rely on the Jews for the observance of Islamic occasions.


No lunar calendar could be made solely on the basis of the New Moon (Conjunction) as it occurs at any time of the day or night without repeating the cycle for centuries.                                                               

The Islamic day begins after sunset. The Islamic month begins after a crescent is visible on the 29th or 30th day. If a crescent is not visible on the 30th day then the count of the days is wrong.       

or more than 2,000 years various calculations were used to predict the earliest visibility of the crescent. However, no criterion is ‘absolutely accurate, and universally applicable’. Moon’s visibility depends on several factors, some of which can be accurately calculated. However, atmospheric conditions are beyond human control. Some Tabi’in, Muhadditheen, and Fuqaha accepted the calculations for determining the beginning of an Islamic month.


The astronomical calculations for the moon, including its conjunction, and lunar eclipses, etc. are accurate to the fraction of a second.                                                                              

The astronomers differ only in predicting the earliest visibility of the crescent. Once the Muslim governments which are using different criteria unify and define what they want the astronomers to calculate then most of the confusion will dissipate. Despite drawbacks, the human knowledge has reached the stage where the astronomical calculations can determine WHEN THE CRESCENT WILL CERTAINLY BE VISIBLE AT ANY PLACE. To overcome the present confusion the Committee for Crescent Observation suggests:                                              



If, for any reason a crescent is seen a day earlier, which would seldom happen, then the Muslims should not fast the next day, but the Eid prayers should be performed on the date fixed earlier.                                     

The present obsession with the ‘UNITY’ of the Islamic dates has forced many well-meaning people to neglect the basic issues of the lunar Islamic calendar. The Ulema and the experts must sit down and agree on some basic principles. The earliest it is done the better the chances are that the present chaos will disappear.