A few years ago ISNA and FCNA came out with a strange position on how to set the Islamic calendar. Traditionally, the only two opinions have involved actual sighting of the moon to officially declare the start of the new month. From what I understand, the FCNA opinion substitutes the sighting requirement with calculations (as opposed to simply supporting sighting with calculations, which is totally fine).

Is my understanding correct, and if so, what is the evidence they present to support this opinion?

  • 1
    What is your question? Is this a simple yes-or-no "Did FCNA do that?" question?
    – Flimzy
    Jun 19, 2012 at 23:27
  • No, I'm asking about their juridical process and proofs. I know there was a paper by Dr. Zulfiqar Ali Shah floating around a while ago but I'm unable to find it.
    – Ansari
    Jun 19, 2012 at 23:28
  • They have been wrong about the start of Ramadan for most of the last 10-15 years. See the www.moonsighting.com archive. The funny thing is that the moonsighting website's prediction on the visibility of the moon has predicted the correct day every time I used it about 2-4 weeks in advance.
    – user13203
    Feb 6, 2016 at 4:09

2 Answers 2


There is this 40 min explanation in English by Shaykh-ul-Islam Dr Tahir-ul-Qadri available on youtube

It explains the hadith and explores the semantics of the word "Ru'ya". He states that no hadith uses "Ru'ya Aien" (eye sighting). Further elaborates different semantics including knowledge, to think, to calculate and so on.

He concludes by saying that eye sighting is one way of knowing. Calculations are another, since Sun and Moon have fixed orbits, and a lunar cycle is 29 days, 12 hours, 44 mins, 3 secs hence should be calculated. He even presents evidence from Quran that Sun and Moon were created to be used towards creation of an Islamic Calendar.

Hence, calculations are not only permissible, but desirable as it eliminates doubt and debate.


There is a difference of opinion on the issue of using astronomical calculations to determine time of fasting and the like. The most correct opinion according to most of the well known scholars is that it is not permissible to depend on calculations (Astronomical Predictions) for Sawm (Fasting), because that is contrary to Sunnah.

The Prophet (peace and blessings be upon him) stated, Begin fasting on seeing the new moon (of Ramadan), and conclude up fasting on seeing the new moon (of Shawwal), and if the sky is overcast (and you cannot see it), complete the term as thirty (days of Sha`ban.) [Narrated by Muslim]

The Sunnah is to depend on moonsightings only for Islamic rulings.

Source: Depending on calculation for Fasting


As for the unification of the calendar through astronomical calculations, there is no harm in relying upon them in administrative matters and the like.

To make it impermissible, you need textual evidence.

Source: Relying on calculations for Calendar

  • @ashes999 By calculations, I meant the astronomical predictions.
    – Abdullah
    Jun 21, 2012 at 14:57
  • 1
    I know what you mean. But you can't call it impermissible. Scholars who use calculations quote this exact hadith as their proof. You should cite it correctly as difference of opinion "but the correct opinion inshaAllah is ..."
    – ashes999
    Jun 21, 2012 at 16:40
  • @ashes999 Okay, makes sense. I did not call it impermissible (I have no authority to do so). I have cited the fatawaa of Ibn baz (rahimahullah) who states it is impermissible. But, if there is a difference of opinion, I can edit it, Insha Allah.
    – Abdullah
    Jun 21, 2012 at 16:44

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