Moon sighting and astronomical calculations – the Islamic perspective


by Shaykh Ahmed Abdul Mujeeb Qasmi Nadvi (translated by Muhammad Owais Jafrey)


Islamic Shari’ah (jurisprudence) mandates Fasting as obligatory. There are only two ways to ascertain the beginning of Ramadan. Either the sky is clear to see the new moon or completion of the 30 days of Sha’baan in case it is cloudy. Allah (SWT) says in Aayah 185 of Surah Al-Baqarah: “…”


Prophet (SAW) said: “Begin fasting and end it after you have seen the moon. If it is hidden for being cloudy, then complete the 30 days of Sha’baan, unless the moon is sighted.” [Nisa’ee].


According to  Abdullah bin Umar (RA) Prophet (SAW) said: “Do not begin fasting without seeing the moon of 29th and don’t stop without seeing it. If it is not visible due to clouds and smog, then observe it for 30 days.” [Bukhari and Muslim]


According to yet another tradition Prophet (SAW) said: “The month is surely of 29 nights, hence don’t start fasting unless you see the Ramadan moon, and if the moon remains invisible, then consider 30 days of Sha’baan to begin Ramadan.


These traditions prove that Prophet (SAW) based the setting of the month of Ramadan on sighting of the crescent, and not on mental or mathematical reasoning. According to authentic Arabic lexicons like Zamakhshari’s “Asaas-ul-Baaligha, and Imam Abu Mansur Tha’alibi’s “Fiqh-al-Lughah” the Arabic word “Ru’yat” means to see something with the naked human eye.


There exists a difference of opinion among scholars about determination of Ramadan, Eids, and other months of Islamic lunar calendar. The classic scholars like Ibn-e-Qutaibaand others scholars of Basra (Iraq), astronomical calculation can be trusted. Their argument is based on “qiyaas”, speculation and conjecture, which still remains a supposition as compared to seeing and witnessing the moon with the human eye. [Al-Majumu]


The celebrated scholars like Imam Abu HanifaImam Shafa’eeImam Maalik, and Imam Ahmad bin Hambal don’t believe in the astronomical calculations. Beside the traditions I have mentioned, one can find many traditions in this context in Hafiz Ibn-e-Hajar’s well- known work “Fatah-ul-Baari”, volume 4, page 152.


Islamic message is universal and takes into consideration the needs and limitations of the entire humanity. In the area of worship, the direction of the Qiblah for example, if hard to determine is left to the understanding of the individual. Similarly the timings of prayers are regulated by the motion of the earth, similarly the determination of the Ramadanand the two Eids has been made simple and straight, which is sighting of the moon. It does not require any exercise in astronomical calculations which are secondary and not primary in nature.


Once Prophet (SAW) said: “We are unschooled people and have little to do with calculations; at one time the month is 29 days, at another it is 30.” [Bukhari]. He (SAW) has solved the problem in simple and easy terms for it to be understood by a common man.


Ummul Momineen Sayyidina Aa’yesha (RA) says: “Prophet (SAW) was more particular about the moon of Sha’baan than any other month. He used to start fasting after seeing the moon, and in case if was not seen due to clouds, he used to fast for 30 days.”


Prophet (SAW)’s life is an ideal life style for a Muslim. The interpreter of the Holy Qur’an Imam Abu Bakr Hassaas Raazi, writes in “Ahkaam-ul-Qur’an”: The command of fasting is for everyone and has been subjected to the sighting of the moon. Since ‘Fasting’ is worship, it is to be followed in letter and spirit by all and should not be limited to the knowledgeable few.” [Ahkaam-ul-Qur’an, volume 1, page 201, and ‘Fatah-ul-Baari, volume 4, page 159].


Imam Nawawi (RehmA) in his celebrated work entitled “Sharh-e-Sahih Muslim” rightly comments that only a few people are aware of the astronomical calculations. The common people would have faced much hardship if it was to be made a rule. Islamic Shari’ah sets only those rules and regulations which are easy to follow by the majority.”


Allama Ibn-e-Rushud Qurtabi Maaliki writes that Prophet (SAW) conditioned the fasting with the “Ru’yat”, i.e. the actual seeing of the moon with the naked eyes. He adds that there is a consensus of opinion of the Ummah on this issue.


The “Ru’yat-e-Hilaal” (sighting of the crescent) issue has in its support many traditions of  Prophet (SAW) quoted by many luminaries like  Umar,  Ali,  Abdullah bin Masood,  Aa’yesha,  Abu Hurairah,  Jaabir bin Abdullah,  Bar’aa bin Aazib,  Huzaifah bin Yamaan,  Abdullah bin Abbas, and many other companions (RAjmaeen).


Let me quote few opinions of some major scholars and jurists to give you an idea that all are unanimous in their opinion with regards to the conditioning of fasting to the sighting of the moon:


  1.  Abdullah bin Umar (RA) didn’t believe in astronomical calculations and used to break his fast with the commoners. (Al-Ashbah, by Ibn-e-Nujaim al-Misri)
  2. Imam Sirhasi (RehA) considers it incorrect to turn to astronomical calculations.
  3. Ibn-e-Arabi says that referring to astronomical calculations is a mistake and should be avoided. (Ahkaam-ul-Qur’an, volume 1, page 82)
  4. Imam Baghvi says that dependence of the beginning or the end of fasting on astronomical calculation is wrong. (Al-Majmoo of Imam Nawawi).


  1. Hafiz Ibn-e-Taimiyah (RehmA) opines: “There is no doubt that in the light of the traditions of Prophet (SAW) and the consensus of opinions of his (SAW)’s companions, dependence on astronomical calculations are not to be trusted.
  2. Hafiz Ibn-e-Hajar writes that the practice of the early puritans rejects the notion of dependence on astronomers. [Fatah-ul-Bari].
  3. Imam Qurtabi says that opinions of the astronomical calculators shouldn’t be followed. (Ahkaam-ul-Qur’an).
  4. Shaikh Muhammad Saawi Maliki (RehmA) says that the opinion of astronomers cannot be a proof of sighting of the moon. [Sharh-e-Al-Zarqaani, volume 2, page 254].
  5. Allama Nujaim Al-Misri says that astronomers’ opinions are not trust worthy. [Al-Behr-ur-Raa’iq].
  6. Allama Shaami writes that the argument of astronomers with regards to the dawn of a new month is not to be trusted, because Shariah clearly subjects the beginning of fasting to the visual sighting of the moon and not on the astronomical principles and regulations. [Rasa’il ibn-e-aabideen. Volume 1, page 249]
  7. The well know jurist of the Islamic world, Dr. Wahba Zuhaili writes: “Calculations of the astronomer cannot prove the sighting of the crescent. His calculations of night and day are based on the rotation of the earth and the result of his work is neither good for him nor for others. Islamic Shariah has attached this issue not to the existence of the moon, but sighting of the crescent. Even if their opinion is considered right in theory, its practice is incorrect.
  8. Academy of Islamic Jurisprudence, Makkah Al-Mukarramah has resolved the issue in a statement which reads: “The guiding principle on this issue for the Muslim Ummahis to follow the visual sighting of the moon and not to act on astronomical calculations.


Ijtihaad (re-interpretation of the Islamic Law) is only possible on issues where Qur’an or Sunnah may not be clear to provide scope for speculation. Traditions of Prophet (SAW) are very clear about sighting of the moon; hence Ijtihaad on this issue is neither possible nor permissible.


Shari’ah preferred sighting of the moon over astronomical calculations because of its own prudence and expediency, which is expressed at times and not expressed at other times. Muslim Ummah is unique and always maintains its individual uniqueness. It has its own calendar to regulate its worship, its festivals and affairs. Its supreme distinction lies in its universal application to young and old, men and women, and rich and poor.


Volumes can be written and have been written on this subject. The essence of all that has been written and said is that in the light of the traditions of Prophet (SAW), and the authentic opinions of jurists and scholars, Islamic months are regulated by the seeing and witnessing of the moon and not by astronomical calculations. Following what Prophet


(SAW) did or said is the key to seek Allah (SWT)’s pleasure and that is our only option. May Allah (SWT) enable us to practice what is right and save us from what is wrong. Aamin!