Calculated Islamic Dates?
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
Lunar calendar dates may be
calculated based on any of the following:
1. The New Moon
2. Visible Crescent moon: Locally visible vs. Globally visible
3. Assumed Visible Crescent Age, Elongation, crescent width, etc.
The New Moon
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
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:
geocentric conjunction occurs before sunset.
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)
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
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
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.