With the Name of Allah, All-Merciful, Most Merciful
Reflections on
Moonsighting
Dr. Usama Hasan
(Al-Tawhid Mosque &
formerly, Royal Observatory Greenwich)
Updated:
Sha’ban 1430 / August 2009
Synopsis
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Ayat, Signs …
Surah Names
The Sun
The Moon & Crescent-Sighting issues
Ayat, Signs …
“We have made the sky a protected ceiling;
But they turn away from its Signs!”
(Al-Anbiya’, The Prophets, 21:32)
“Among His Signs are the Night and the Day, the
Sun and the Moon:
Prostrate not to the sun and the moon,
But prostrate to Allah who created them …”
(Fussilat, Signs Explained, 41:37)
Chapters of the Qur’an Named
After Astronomical Phenomena
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Al-Shams (The Sun)
Al-Qamar (The Moon)
Al-Najm (The Star)
Al-Buruj (The Constellations or Zodiacal Signs)
Al-Tariq (The Piercing Star)
Al-Fajr (Dawn)
Al-Layl (Night)
Al-Duha (The Forenoon)
Al-’Asr (The Late Afternoon)
Al-Falaq (Daybreak)
Earth’s Annual Motion: Seasons
Annual Motion of the
Sun, Moon, Planets & Stars
“Lord of the Two Easts, Lord of the Two
Wests!
So which of the favours of your Lord will
you deny?”
(al-Rahman 55:17-18)
“Lord of the East(s) and West(s) …”
(Muzzammil 73:9, Ma’arij 70:40)
Annual Motion of the
Sun, Moon, Planets & Stars (Q. 55:17)
SUMMER SOLSTICE
EQUINOXES
WINTER SOLSTICE
N
E
Easts
(Multiple, Two limits)
S
W
Wests
(Multiple, Two limits)
N
The Moon - Basic Facts
• The Earth travels around the Sun once
every 365 days (& 6 hours)
• The Moon travels around the Earth once
every 29 ½ days
– A lunar year of 12 lunar months has 354 days
• Phases of the moon result from parts of
the Moon reflecting the Sun’s light towards
the Earth
• A lunar month has either 29 or 30 days
(hadith)
Phases of the Moon
Looking for the New Crescent
• Only visible after sunset
• Must wait for the sun’s glare to die down
• Experience shows that the best time to
see the crescent is about 20 minutes after
sunset (when the sun is 5° below horizon)
• Perfect timing if the Sunnah is followed
(Salat al-Maghrib should be fairly short)
• Look at the western horizon, near where
the sun set
A Good Test of Moonsighting
“When the crescent moon is visible
somewhere on earth, it must be visible at
all points west of it [on the same latitude]
with a clear horizon.”
www.moonsighting.com
This simple principle is also agreed by the
scholars of Islamic Law, e.g. the Shafi’is,
Ibn Taymiyyah, etc.
‘Id al-Fitr Hilal, Shawwal 1425
(Brunei)
Moonsighting - History
• The Islamic calendar is a purely lunar one
• Islam abolished the Pre-Islamic Arabian method
of intercalation
• Until relatively recently, the start of each lunar
month was determined purely by observation of
the new crescent moon
– If cloudy, use a simple alternating 29/30 day rule
• Communication constraints meant there was no
controversy across the vast Muslim lands
Moonsighting – Islamic Law (1)
• The Shari’ah (Sacred Law) covers all
areas of life
• Basic rule: crescent-sighting establishes
the new month
• Calculations: controversial; different views
– Cannot be used to determine new month
– Can be used to reject false crescent-sightings
– Can be used to determine new month
Moonsighting – Islamic Law (2)
• Applicability of a valid crescent-sighting
• One view: ikhtilaf al-matali’ (“multiple
horizons”)
– Crescent-sighting applies only “locally”
– Nowadays: each state has its own horizon
• Another view: ittihad al-matali’ (“unified
horizons”)
– A single sighting applies for the whole
(Muslim) world
Views of Ibn Taymiyyah (8th/14th C)
Hilal-sighting depends on how easterly or westerly the
location is, so if the hilal is seen in the east, it must
be seen in the west, but not vice-versa. This is
because sunset occurs later as we move further west.
If the hilal has been seen in a particular location, its
illumination and distance from the sun and its rays will
increase at sunset to the west, and will therefore be
more easily visible. The reverse case does not apply,
i.e. if the hilal is seen in the westerly location, since a
factor in its visibility may have been the later sunset
there, such that the hilal’s distance from the sun and
illumination will have increased, whereas it was closer
to the sun in the easterly location.
Views of Ibn Taymiyyah - 2
The fixed rule (dabit) here is that this matter
depends upon information, due to his saying,
“Fast upon its sighting.” Therefore, whoever is
informed that the hilal has been sighted,
Ramadan has conclusively begun for him, with
no consideration at all given to distance (i.e. no
matter how near or far he is from the place of
sighting). This corresponds to Ibn ‘Abdul Barr’s
statement that there is no effect of news
reaching built-up areas after the month is over,
unlike places where news arrives during the
month, where it may have an impact.
Views of Ibn Taymiyyah - 3
He made the hilals markers of time for the people: they cannot be so
unless they are observed via sight and the news transmitted via
hearing. If there is no observation, there is no marking of time, so
they are not hilals. This is the most that can be established via
the senses, since to specify the location where the hilal first
appears by way of calculation is not correct in the least, and I
have written something about that. [NO LONGER TRUE]
This matter depends on the latter also, for it is not within human
capability to determine specific times and locations for
seeing the hilal. [NO LONGER TRUE] People can only be sure
about what they see with their eyes or hear with their ears. Since
the obligation upon the person who sees the hilal is to follow his
sighting, and upon the person who does not see it is to follow the
news that he hears, someone who neither sees nor hears
anything has not achieved ihlal.
Majmu’ Fatawa Ibn Taymiyyah, vol. 25, pp. 98-113
Background - Calculations
• Accurate calculations for the position of the
moon have been around for thousands of years
– E.g. solar and lunar eclipses
• However, calculation of the visibility of the new
crescent moon has only become significantly
accurate over the last ~20 years
– Yallop, Ilyas, etc.
• Usually, the moon needs to be 15-25 hours old
before the crescent is visible
– Using conjunction (“astronomical birth”) means the
month will start one day too early
Calculating Crescent Visibility
• Simple prediction rules have existed for millenia
(ancient Babylon, Greece, classical Islam, e.g.
al-Bayruni, etc.)
• Modern criteria have been developed by:
– Bernard Yallop (ex-director of the Royal Observatory
Greenwich)
– Mohammad Ilyas (Malaysia)
– Schaefer (kept the details secret)
– Odeh (Jordanian Astronomical Society)
Calculating Crescent Visibility (2)
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Moonsighting.com is based on Yallop/Ilyas and
uses five factors only:
1. The angle between Sun and Moon
2. The (angular) height of the Moon above the
horizon
3. Earth-Moon distance
4. Earth-Sun distance
5. A measure of pollution in the atmosphere
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Moonsighting.com’s predictions have proved
accurate every month since 1994!
Combining Shari’ah & Science
1. Accept local sightings, as well as those
from the East of your location, but not
West. (Simple physics)
2. Instantaneous telecommunications must
be taken into account. (Ibn Taymiyyah:
the matter depends on information)
3. Calculations are now precise enough to
decide Islamic lunar months, unlike in the
time of mediaeval, classical scholars
Crescent Visibility Curve
– Thurs 20 Aug 2009
Crescent Visibility Curve – Fri 21 Aug
2009 (1st night of Ramadan 1430)
Crescent Visibility Curve
– Sat 22 Aug 2009
(end of 1st day of Ramadan 1430)
Ramadan in 1430 (2009)
• Based on (1) “sightings from the east” and
(2) instant telecommunication, we have:
– 1st day of Ramadan for the entire world should
be Saturday 22nd August 2009
– 1st Shawwal (Eid al-Fitr) for Europe/US should
be Sunday 20th September 2009
– So Ramadan is 29 days long in Europe/US
Towards a Unified Lunar Calendar
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With accurate calculations of crescentvisibility, a worldwide lunar calendar is
now possible
There are 3 major possibilities:
1. Use the visibility curve as an ILDL
2. Fix everything wrt one place, e.g. Mecca
3. Compromise: the Unified Hejra Calendar
(divide the world into three time zones)
Proposal 1: Crescent-Visibility curve as
ILDL (International Lunar Date-Line)
30 Shawwal 1426
1 Dhul Qa’dah 1426
Proposal 2: Fix everything wrt one
place, e.g. Makkah
30 Shawwal 1426
Makkah
1 Dhul Qa’dah 1426
Proposal 3: the Unified Hejra
Calendar (www.icoproject.org)
Western Region
Central
Region
Eastern Region
Proposal 3: the Unified Hejra
Calendar (www.icoproject.org)
Western Region
For Dhul Qa’dah 1426, ILDL
coincides with the Solar dateline
Central
Region
Eastern Region
The MOONWATCH Project
• Launched 1st Oct 2005 & will run for several
years (www.crescentmoonwatch.org)
• A mass-experiment for the UK public
• Part of Einstein Year (2005 is 100 years since
the publication of Relativity theory)
• Everyone is encouraged to look for the new
crescent every month and report their
observations via the above website
• Will help improve HM Nautical Almanac Office’s
crescent-visibility calculations, in sha’ Allah
The MOONWATCH Project
• Since October 2005 (Ramadan 1426),
about 3000 observations of the hilal, both
positive and negative, have been reported
to the Moonwatch website from around the
world
• ALL the results are, so far, consistent with
the current Greenwich model for predicting
the visibility of the hilal
Misconception: “Crescent cannot
be seen in the UK …”
• … Er, yes it can!
• Moonwatch results confirm this
– Less favourable climate than some other countries
– The more observers around the UK, the more chance
of a break in cloud
• Here is a video of a first-night, 32-hour old
crescent + Venus from my back garden in
London (Muharram 1428 / January 2007):
http://www.youtube.com/watch?v=dfz0Sv5lyWM
Links
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www.crescentmoonwatch.org (Moonwatch)
http://websurf.nao.rl.ac.uk (HM NAO)
UK_Islamic_Astronomy yahoogroup
www.moonsighting.com (Dr. Khalid Shaukat)
www.jas.org.jo (Jordanian Astronomical Society)
www.icoproject.org (Islamic Crescent
Observation Project)
• Unity1.wordpress.com (personal website)