Calculated Islamic Dates?                                                        Dr. Omar Afzal

A recent article By Dr. Zulfiqar A. Shah (June 2006) in support of  “Calculated” dates of Ramadan and Eidain has been widely circulated. The article repeats most of what has already been available (Qaradawi: Kaifa nata’amal ... pp.145-154, Afzal (1997:False Sighting… ,Rebuttal of Qaradawi (1989), Guessoum (1997), etc.

The 29-pages long article is short on suggestions about Islamic calendar and vague about:

a. What is to be calculated? and
b. Will the calculated dates take into account the moon’s visibility or ignore it altogether?

Lunar calendar dates may be calculated based on any of the following:

1. The New Moon phase             (Conjunction)
2. Visible Crescent moon:            Locally visible vs. Globally visible
3. Assumed Visible Crescent       Age, Elongation, crescent width, etc.

The New Moon (conjunction)

The New Moon is not the “Hilal.” At the New Moon phase, the moon is completely dark. The crescent formation does not start until the moon’s elongation from the sun exceeds 7 degrees.

The New Moon (conjunction) date could be roughly calculated for more than two thousand years. The moon’s approximate “local” visibility could be computed since Babylonians, Hindus, Chinese and Jews started using their lunar calendars. However, a more precise global lunar visibility computation was made available in 1978 by Dr. S. Kamal Abdali. During the last three decades RGO’s Yallop and others have tried to improve the prediction of the earliest lunar visibility. (For details see Monzur’s: www.MoonCal.com).

The Umm al-Qura Calendar              After 1422 AH            (http://www.phys.uu.nl/~vgent/islam/mecca/ummalqura.htm)

From 1423 AH (15 March 2002) onwards, the Saudi Institute that calculates Umm al-Qura calendar (TUQ) has modified its rules as follows:

            If on the 29th day the following conditions are satisfied, then the next day is the first day of the new lunar month:

            1. The geocentric conjunction occurs before sunset.

            2. The Moon sets after the Sun.

Otherwise, the current lunar month will last 30 days.

Obviously, the latest Taqweem Umm al-Qura rules adopted from March 2002 totally ignore the Moon’s visibility in Makkah or anywhere in the world.

Let us consider TUQ’s calculated Sha’ban 1427 (25 August) and Shawwal 1427 (23 October) 2006 dates.

August 23, 2006    (New Moon Phase at 19:11 UT)

Moon’s age in Makkah:                          -3 hours 24minutes            (The Moon is not New yet)

Sunset                                                        6:45p

Moonset                                                     6:43p            (The moon sets two minutes before the sunset)

Moon’s position at sunset in Makkah:    Angle: 2.8 degrees            Altitude: -0.4 degrees

By TUQ above rule the first date of Sha’ban is calculated as August 25.

Obviously, this moon could not be visible on August 23 (the conjunction date) because its age in Makkah is minus –3h 24m and it is setting two minutes before the sunset.

Will the moon be visible next day (August 24) in Makkah? It is very unlikely, as the moon’s age at sunset is only 20 hours and 36 minutes, it angle 9.4 degrees and its altitude only 6.9 degrees.

Sha’ban moon will NOT be visible anywhere in the world on August 23, and only in parts of South America on August 24. “Earliest visibility” based Sha’ban dates are August 25 for South America and August 26 for the rest of the world.

October 22, 2006    (New Moon Phase at 05:15 UT)

Moon’s age at Makkah:                           9 hours 36 minutes

Sunset                                                        5:51p

Moonset                                                     5:52p            (One minute after the sunset)

Moon’s position at sunset in Makkah:    Angle: 5.5 degrees            Altitude: 0.2 degrees

Following TUQ rule Oct 23, 2006 is set as the first date of Shawwal 1427.

Obviously, a moon setting only one minute AFTER the sunset and hardly above the ground at sunset CANNOT be visible in Makkah. Even on Oct 24, a crescent moon will be difficult to see at sunset in Makkah as the moon’s altitude is only7.8 degrees and it is setting only37 minutes after the sunset despite its age (33 hours and 36 minutes) and angle= 16.1 degrees.

On Oct. 22, 2006 Shawwal crescent moon will NOT be visible anywhere in the world. On October 23, it will be visible mostly in southern hemisphere from New Zealand to Durban and Santiago (Panama). A strictly “visibility based” Shawwal should begin on Oct. 23 in South America, on Oct. 24 in most of the world and on Oct. 25 in northern regions of Asia and Europe.

There are many more complications in calculating lunar dates. For example on June 25, 2006 (Jumada II) the moon’s age in Makkah is zero hours though it is setting 6 minutes after the sunset.

Muslim experts should carefully evaluate the intricacies of “Calculated dates” before issuing a Fatwa to replace them for “Sighted” moon dates of the Qur’an and the Sunnah.