Dates – Astronomy of Moon-sighting
By Dr. Omar Afzal
Committee for Crescent Observation Intl.
Fixed Islamic dates are the need
of the hour.
Who does not want that the dates of Ramadan, Eids
and the Hajj be precisely known so that the Muslims
can plan their rituals ahead of time? The present
chaos and waiting till midnight to know if to pray
Taraweeh, or rent a place for large congregational
Eid prayers, taking a day off from schools, colleges,
businesses or professional jobs are not only unbearable
but also make the Muslims a butt of ridicule.
The attempt to find a solution started long ago.
Almost every Muslim astronomer from the tenth century
on attempted some theoretical model to predict the
moon’s earliest visibility. However, the zone
of uncertainty between “the “Possible”
and “Not Possible” was so wide that
success eluded all.
Data carefully collected during the last hundred
years provided very valuable information. Now we
can calculate the probable Islamic lunar dates for
various parts of the world. However, lunar calculations
do not predict moon’s visibility with 100%
certainty. Abdali (1979) suggested computing broad
visibility of the crescent moon. Kahf (1980) proposed
“News” from any Muslim country.”
ISNA Fiqh Council (10 June, 2006) has proposed purely
calculable fixed Islamic dates, based on the “conjunction
before 12:00Noon at GMT”, eliminating the
The Qur’an (2:189) makes “Ahilla”
(visible crescent moons) the “Mawaqeet”
(determinant of the beginning of the Islamic month).
The Messenger (SAW) put Allah’s command into
practice. He was aware of the Jewish calendar used
by the Jewish tribes in Medina and the accuracy
of its calculation. (The Jewish calendar was calculated
by the conjunction around Jerusalem, with some crucial
adjustments and Nasi - adding an extra month every
three years.) But the Prophet (PBUH) asked the Muslims
to use a different method to fix their dates.
To be sure about the Ramadan and Eid dates he carefully
looked for the Sh’aban moon. He began Ramadan
29 or 30 days later. He instructed the Muslims to
begin Ramadan only after a sighting of the Ramadan
moon, and not start it a day earlier on the “suspected
date” (yaum al-shakk). To avoid Eid al-Fitr
on the last day of Ramadan, he instructed us to
stop fasting only when the Shawwal moon was sighted
at the end of the fasting period. In case the clouds
or haze obstruct the moon’s visibility on
the 29th day then the Muslims complete the month
to thirty days. A moon is always visible on the
His Khulafa and the companions kept his practice.
As the need grew the Muslim jurists came up with
detailed solutions, according to their knowledge
of the geographical facts and the trends in reporting
moon’s visibility. Some required only one
or two witnesses from a town and others went for
50. When some jurists noticed deliberate mistakes,
they increased the number to five hundred in the
same town to attain certainty about fixing these
religious observances. None of them ever discarded
the moon’s naked-eye, local visibility. All
1. Ahillah are the “visible crescent moons.”
2. “Ru’yah” is to “perceive
with the eye” after looking at an object.
3.“Ghumma” means “overcast”(in
the context of the Hadith).
Any suggestion that the word “Ra’a”
means mere “knowledge of the moon in the sky”,
or that the Hilal means “a black invisible
moon” was not known a few decades ago and
rejected almost unanimously. Extending the local
horizon of sighting was rejected by Ibn Abbas and
others, and allowed to some distance not exceeding
the distance between Damascus and Median. Extending
the Matla backwards was unheard of. All these suggestions
are denying the very core of the Fiqh and astronomy
Any classical Arabic dictionary will provide the
detailed usage of these terms. All explanatory note
on these Ahadith support the assertion that the
Prophet (PBUH) proposed the simplest, practical
solution to a contested issue between the “Ummi”
Muslims of Medina, and followers of the accurate
but “conjunction-based” Jewish calendar
there. “Go look for the moon. If you see it
then fast/celebrate Eid.” If the moon is hidden
behind the clouds or haze then complete fasting
to 30 days.
This is how the Muslims practiced the words of the
Prophet (PBUH) for the last 1427 years.
The proposed “conjunction before 12:00 noon
GMT” is a slippery solution. Does it mean
calculating “one second after the conjunction”
or “a week after the conjunction and for what
part of the world? What about the revolving length
of the month? There are scores of issues that have
to be solved for a global fixed Islamic calendar.
Now we can easily calculate a “sighted-moon”
based Hijri calendar but only for a large area like
the United States. In most cases, the calculated
date would be verified by the actual visibility
if we use MoonCal’s “A” curve.
Thus fixed dates will give us the level of certainty
as high as 90% and eliminate fasting on “Yam
al-Shakk” and Eid on the last day of Ramadan.
The “zone of uncertainty” causes problems
on a limited number of dates every years. The calculated
fixed dates should be use as a guide to be verified
by subsequent confirmed sightings. They also eliminate
false witnesses claiming from “B or C”
zone that could not be corroborated by observations
at places located west of the claimed sighting.
The real issue is at what point after the birth
of the New Moon (conjunction) the "Visibility
of a Hilal" starts for every person with the
normal vision, and from which point on earth?
Muslim experts, when attempting to fix Islamic dates,
must take into consideration the minimum threshold
of moon's visibility, the shape of the globe, as
well as calendar making rules besides the intricacies
of the Shariah rules. For example, for Eid al-Fitr
2006, the moon by some calculation might become
visible in southern Indian Ocean, but not in S.
Arabia though it is hundreds of miles west of the
initial sighting. Could the sighting in the east
be used to celebrate Eid in S. Arabia although a
crescent moon is not visible there? However, the
Muslims will never accept any attempt to DISCARD
the visible Hilal phase totally.
Astronomy of Lunar Dates
A new solar date begins at180E (Intl. date line).
However, the local date starts everywhere at 12:00
midnight. The day begins when the sun rises at the
place of the observer.
The Matla of the sun for the solar date is counted
from 180E. The earth rotates around the sun and
it takes 24 hours for the sun to be visible over
Similarly, the moon rotates around the earth but
its Hilal generally takes 24 -72 hours to be visible
in most regions of the world. As the sun has only
one Matla, so has the moon. The moon’s Matla
is measured westward from where the Hilal was seen
first. As the first visibility of the moon begins
from a different point on earth and extends in a
parabola instead of north south at any longitude
there is no fixed international dateline. The local
lunar date begins from the sunset, and the month
begins after a Hilal is seen after the sunset.
For fixing the lunar date, we always count from
where the moon is seen first. Any attempt to start
a lunar date backwards, or in places where the moon
could not be seen on that date is technically incorrect.
One should also take into account the fact that
at "12:00 Noon GMT" the solar date at
180W (International Dateline) instantly changes
to the next one. How can the Muslims in the US start
the month when the moon would be seen on the next
The Prophet (SAW) was clearly told about the authentic
calculation of the conjunction for the Jewish calendar.
He followed it for his first Ashura fast. Why did
Allah not ask Muslims to adopt the practice of the
previous Shari’ah? Why did the Prophet (SAW)
ask the Muslims use a different method of fixing
the Islamic dates?
Only the “conjunction” is calculable,
and it occurs at all times of day and night. No
lunar calendar ever used exactly calculated conjunction
for fixing its date. All had to adjust the conjunction
day/date to a fixed point of time of the day and
from a fixed place (Jerusalem, Ujjain, etc.)
There is no "authentic" calculation of
the Hilal" even today after 1427 years. The
calculations of the Hilal are only for a broader
region and the dates are calculated to reduce mistakes,
and not replace the actual sighting.
Recent attempts to provide Fiqhi justification for
eliminating the visual sighting of the moon and
extending the US horizons to the solar dateline
do not appear to fulfill the basic requirements
of the moon’s visibility in the United States.
Ignoring calendar computation rules, and geographical
facts has led a few to interpret crucial terms like
Hilal, Matla’, Ru’yah, and Shahadah
to negate what has been a unanimous understanding
and practice of the Muslims for the last fifteen
centuries. Our desire to solve a complicated calendar-making
problem by some naive solution should not obstruct
our reasoning to the core Shariah requirements.
We should also educate the Muslims to abide by the
Shariah standards, and not by what some countries
are doing. May Allah help us. Ameen.