Our Goal
The goal of the Islamic Computational Astronomy
Network (ICAN) is to:
• Set up a single, global standard for the Islamic
calendar based on:
– Islamic requirements
– Astronomical facts
Results:
• The entire Islamic world can establish a uniform
global Hijri calendar
• Muslims everywhere in the world have the
same Hijri dates (not two or three)
visit www.islamicmoon.com
The Format of the Talk
• The talk will be broken down into three parts:
• PART 1: CALENDARS
– How a calendar is made
– How Muslims fixed their calendar
– Question and answer session
• PART 2: THE MOON
– How the moon is sighted
– Question and answer session
• PART 3: A NEW GLOBAL CALENDAR
STANDARD
– A new proposed global standard
– Question and answer session
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Part 1 - Calendars
Muslims in North America follow THREE
Hijri Calendars
- Calendars from ME countries.
- Moon SEEN anywhere in 48 contiguous states
- “Locally” visible moon (CT Council of Masajid)
Muslims started Ramadan 2005 on four solar
days/dates (instead of one lunar day/date).
Oct. 3 Monday: Nigeria (some Sunday, Oct. 2 also)
Oct. 4 Tuesday: S. Arabia, M East, followers of Saudi dates)
Oct. 5 Wed.: Australia, Indonesia, Malaysia, Brunei, Turkey,
Africa, Europe, Americas
Oct. 6 Thurs.: Bangladesh, India, Pakistan, Central Asia
Eid al-Fitr 2005 was celebrated on four different
days/dates:
Nov. 2 Wed: Nigeria, Libya
Nov. 3 Thurs.: S. Arabia, M East, Indonesia, EU, USA (ISNA)
Nov. 4 Friday: S. Africa, UK, Canada, USA, India, Pakistan
Nov. 5 Saturday: Northern India, etc.
Why this chaos?
Muslims do not agree on when to
begin an Islamic month.
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Calendar – Making Options
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You can make a calendar
by using the sun or the
moon
People have used different
methods to make either
calendar for thousands of
years
The Islamic calendar is
lunar, unlike the solar
calendar
• The New Moon time and
Lunar calendars
date could be fairly
accurately calculated for
• Babylonian
more than 2000 years.
• Jewish
• None of the lunar
• Hindu
calendars starts from the
New Moon (Conjunction)
• Chinese
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• Islamic
Two Major Challenges
a. Accurately predicting moon’s earliest visibility
b. Uniform global fixed dates of Hijri Calendar
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Calendars are Global, not Tri-Zonal
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Why Muslim Dates Are a Mess?
•
Some start Ramadan;
•
By a visible moon (India,
Pakistan, Bangladesh,
Morocco, S. Africa)
From the Moonset after the
sunset (Saudi Arabia, Egypt
and the M. East)
On the New Moon date
(Libya, Tunis, etc.)
Moon’s fixed elongation or
altitude (Indonesia, Malaysia,
Turkey, etc.)
•
•
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Only dates based on the ‘earliest
visible moon at sunset’ fulfill
the Shariah requirements.
Do we have to see the Hilal to
start and end Ramadan and
other months? YES. visit www.islamicmoon.com
Lunar Calendar
• A lunar calendar depends on the moon’s phases
• Earlier, you could not predict exactly when and where a
moon would be seen
• Now we can do this with modern computers
• Before the modern communication age, people observed
their lunar calendars locally. It was not possible to
coordinate between towns, countries and continents
• If it was cloudy, people couldn’t see the moon. They had
to complete 30 days though the moon was seen in the
nearby town
CONCLUSION:
– The old ways of calendar-making, where every
village and town observed its own dates, is no
longer correct. Tri-zonal or bi-zonal calendars are
equally invalid. visit www.islamicmoon.com
QUESTION AND ANSWER
SESSION
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Part 2
- Qur’an: Hilal is Miqaat
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Hilal and Not the New Moon
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Ittihad vs. Ikhtilaf al-Matali
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Lunar Calculation is Fine
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Moon-Sighting Controversies
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Moon-Sighting
Involves Two Parts
• There are two parts to moon-sighting
– How the moon revolves around the Earth
– How, when, and where people on the ground
see the moon
Moon Basics
• The moon revolves around the earth (need an animatic to
show this)
• As the moon moves around the earth, its phases change
from the new moon to full moon and back to new moon
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Computed New Moons for 2000-2019
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Data for Ramadan 1427
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Moon’s Rotation Around Earth
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Sidereal & Synodic (Conjunction) Month
• The moon rotates
around Earth
• Sidereal rotation takes
27 Days, 7 Hrs, 43
Mins, 11.6 Sec
• Synodic month
(Conjunction to
Conjunction) is 29
Days, 12 Hrs, 44 Mins,
2.9 Sec
• The moon is not visible
on the conjunction
date
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This is the New Moon (Geocentric Conjunction)
New Moon
Hilal
• Arabic term for the conjunction phase
of the moon is not “Hilal” but “al-Qamar
al-Mawlid” (new born-moon)
• Hilal (plural Ahilla) is the earliest visible
waxing crescent moon after “Mahaaq”
• “Mahaaq” are the dark nights between
two lunar months when the moon is
hidden for observers from the surface
of the earth.
• The New Moon (Geocentric
conjunction) could not begin a lunar
month because:
– The New Moon occurs at all times
of day and night.
– A date has to start always from a
fixed point of time.
– Every month the New Moon occurs
at a different point on the globe
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A NASA Photograph at the New Moon Phase
• The infra-red
scan of the
moon at the
conjunction
shows a full
black moon with
no crescent
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This is the Islamic New Moon (Hilal)
• Hilal (plural: Ahilla) is the
visible waxing crescent
moon of the first two or
three days.
• The term is derived from
the root “Halla” to ‘raise
voice at the first sight of
the waxing crescent
moon
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Moon’s Paths in Various Months
• From different
locations on Earth
in different
seasons, the
crescent moon
appears of a
different shape
and at different
heights.
• If the moon is not
seen on the 29th
evening then on
the next day it
appears 24 hrs.
bigger,12 degrees
higher and
brighter. It stays in
the sky 52 min.
longer too.
• It does not mean
the moon could
be seen in the
previous evening.
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Fixing Dates of Ramadan and Eidain
• Islamic dates are not fixed because
Islamic month may be 29 or 30 days
long
• Islamic day and date begin at sunset
after a moon is seen
• The earliest visible moon can now
easily be computed for any point on
Earth
• Earliest visibility may be by naked
eye or binoculars followed by naked
eye or telescope followed by
binoculars or telescope only
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The New Moon or Hilal?
The New Moon (Geocentric
conjunction) cannot begin a
lunar month (as Qaradawi,
Shakir and others believe)
because:
•
The New Moon occurs at all
times of day and night. (A
date must always start from a
fixed point of time)
•
Every month the New Moon
occurs at a different point on
the globe
A rotating dateline and floating
time made the New Moon
useless for any lunar calendar
•
The Qur’an, the Sunnah
and Fiqh make the
earliest visible waxing
crescent moon (Hilal) the
fixed point (Miqaat) to
begin an Islamic month:
(2:189)
Can we accurately predict
moon’s earliest visibility?
• Yes. For any region,
though not for every
village on the Earth)
• Visibility should be
consistently verified by
naked-eye sighting
visit www.islamicmoon.com
How Astronomers Compute Visibility
•
The Moon’s earliest visibility is no longer a scientific inquiry, and there is no scientific ‘test’ to
prove or disprove a sighting claim. So how to determine the first date of an Islamic month?
Since ancient times, astronomers have tried to predict the likelihood of seeing the waxing
moon by defining minimum visibility criteria. Monzur’s MoonCalc currently supports 13 such
criteria.
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* Babylonian....................
[Age at sunset>24hrs & Lag>48 min.]
* Fotheringham (1910)
[Alt, Rel Azi]
* Maunder....... (1911)
[Alt, Rel Azi]
* Indian/Schoch..........
[Alt, Rel Azi]
* Bruin ........... (1977)
[Alt, Crescent width: 0.5 modified to 0.25 min.
* Ilyas_A........ (1984)
[Alt, Elong]
* Ilyas_B modified Babylonian [Lag:41-49 min for 0-40 degrees Latitude]
* Ilyas_C........ (1988)
[Alt, Rel Azi]
* RGO/CFCO (1981)
[Alt=10 degrees at sunset, Elong:12+/-]
* SAfrican Astro Obs
[Topocenteric Alt, Rel Azi]
* Shaukat........ (?)
[Alt:3.4, Elong: 12.7+ Crescent width: arcmin /1.2)>1]
* Yallop …. (1997/8)
[Rel Alt, Crescent Width]
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This criterion was developed from the Indian and Bruin criteria by Yallop (RGO) from 295
published moon (non)sightings compiled by Schaefer and Doggett. A parameter 'q' is derived
from the relative geocentric altitude of the moon (ARCV) and topocentric crescent width. In
the original technical note byYallop, q was derived at 'best time' (ie sunset + * moonset lag).
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Criterion
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A
B
C
D
E
F
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q Range
q > +0.216
+0.216 >= q > -0.014
- 0.014 >= q > -0.016
-0.016 >= q > -0.232
-0.232 >= q > -0.293
-0.293 >= q
Remarks
Crescent easily visible (*Not always)
Crescent visible under perfect conditions
Need optical aid to find crescent
Optical aid only
Crescent not visible with telescope
Crescent not visible, below the Danjon limit of 7 degrees elongation
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Earliest Visibility
•
How to verify the
earliest visibility
claim?
•
Some 16-20 hours
old moons
Some 20-24 hours
old moons
Some 24-30 hours
old moons
2 days old moon
•
•
•
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Tricky Part: Observing the Moon
• The easy part is to understand how the moon
works
• The tricky part is how people actually observe it
from the surface of the earth:
– How old a moon has to be before the human
eye can see it
– If the sky is clear, why will some people see it
and others will not
– Where it is cloudy or hazy, no one will see it
We can now predict where it will be seen, and
when
visit www.islamicmoon.com
Moon Visibility
• In order to be seen, the moon must be approx. 20
hours old or more;
• 12 degrees away from the sun; and
• 10 degrees above the horizon
(Keep in mind that it will not always be seen, and
not everywhere even if these conditions are met)
• The moon is seen on earth starting at point Y and
its visibility extends westward in a parabola
• Each month, the moon is observed from a
different place as the visibility maps show
• Earliest point of observation is not repeated for
hundreds of years
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Moon-Sighting Historically
• The ancients had no way of
predicting moon’s earliest
visibility accurately. So the
older lunar calendars such as
the Chinese, Indian, etc. used
computational tables to check
the actual observation of the
moon each month
In the Muslim World
The month was fixed by:
-Watching the new moon each
month, or
- Official government or Islamic
body proclamation or
- Other options: (fixed calendars,
month alternating 29 and 30
days)
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Moon-Sighting Challenges
• Computational modeling predicts when and where the moon
will be visible first, but
• If you go by visibility, then you face several hurdles:
1. Sighting starts from a new point each month
(This means that in one month Chicago may see the
Hilal, but people 30 miles east of Chicago will not.
Does this mean that both communities should
observe separate Hijri calendars even though they
are only 30 miles apart? This was quite common until the 1950’s.)
• The answer is NO
• You need to build a uniform calendar based on Shariah and
Geodesic rules
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Every Lunar Month is 29 and 30 Days Long
Ramadan started on Nov. 5 2002 at a different point on
Earth than Shawwal on Dec. 4 2002. This makes
Ramadan 29 days long for the Americas and 30 days
long for the rest of the world.
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Earliest Visibility-Based Lunar Calendars
• Earliest visibility starts
from a different point on
Earth each month, as we
see here
• Only W. Africa and the
Americas could see Safar
Moon on 2/28/06. The rest
of the world saw it on
2/29/06
• Visibility separator curve
requires adjustments for
political boundaries
(Canada with the USA, etc.)
• Extending visibility to
areas outside visibility
separator curve (UK on
Morocco, Europe on Saudi
Arabia, or S. Africa)
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QUESTION AND ANSWER
SESSION
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PART 3 - Global Islamic Calendar
• Islamic lunar month is no less than 29 and no more
that 30 days long (Hadith: Al-Shahru haakadha wa
haakadha…)
• Locally, the Islamic month starts from sunset when the
crescent moon is first observed and continues until a
moon is seen again after 29 or 30 days
• A consistently west-moving dateline based on the
moon’s earliest visibility means:
- Islamic month starts from a different point on Earth
- Every month is 30 days long for some regions and 29
days for the rest
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Modern Astronomical Computations
•
MoonCalc. formalized various
visibility criteria
• A ‘strictly visibility-based’ criterion
has several drawbacks:
a. Visibility is ‘local’ and not ‘global’.
Towns only a few miles apart,
even parts of a mega city might
see moon on two different days.
b. Atmospheric conditions hinder
moon’s visibility
c. Observers mistakes and illusions
(Visibility reports collected from
1900- contain unreliable claims.
d. Moon watches arranged in 1990s
did not produce reliable data.
e. Many moon observers now
compete to break the old
‘records.’
There is no scientific test to prove
or disprove a claimed sighting
to be valid (i.e.: Nov. 2, 2005)
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(MoonCalc)
Global Lunar Calendar Standards
• Muslim astronomical computations for Global
Hijri calendar:
• Abdali (1978)First serious attempt to calculate the
predicted dates of global lunar visibility.
• Minai (1980-81) Detailed analysis of issues involved in
global Islamic lunar calendar
• Charles Evans (1960-) Photographic images of the earliest
visible crescent moons
• Afzal (1986) Proposal for computing a global Islamic lunar
calendar based on the moon’s visibility around 180E
• Imad (1986) First suggestion to make Makkah the starting
point of an Islamic date
• Ilyas (1986) suggested “Probability of moon’s earliest
visibility” for tri-zonal and bi-zonal Hijri calendars
• Turkish (
)
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Reference Articles on Moon’s Visibility
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Ashbrook, J. 1984 Astronomical scrapbook, Sky Pub. Co. Cambridge. M.A.
Bruin, Frans. 1977 The First Visibility of the Lunar Crescent, Vistas in Astronomy. V. 21,
pp. 331-358 (1977).
Caldwell, John A.R. 1999. First Visibility of the Lunar Crescent. South African
Astronomical Observatory.
Doggett, L. E. 1994 “Lunar Crescent Visibility” ICARUS (v.107: p388-403)
Dershowitz N. & E.M. Reingold 1997 Calendrical Calculations. Cambridge University
Press, New York.
Fatoohi, Louay J et al. 1998. The Danjon Limit of First Visibility of the Lunar Crescent. V.
118.
Loewinger, Y. 1995. Some Comments on the Article of Dr. B.E. Schaefer… Q.J.R. Astro
Soc.
Odeh S.M. 1999. Taqweem Nasb al-Khata Fi Tahdeed Awail al-Ashhur al-Hijriya.
Qasum et. al 1997 Ithbat al-Shuhur al-Hilaliyah wa mushkilat al-Tawqit al-Islami. Dar alTaliyah, Beirut.
RGO Astronomical Information Sheets 1987-2005
Schaefer, Bradley E. 1988. Visibility of the Lunar Crescent. Q.J.R. Astro. Soc
Schaefer, Bradley E. 1991. Length of the Lunar Crescent. Q.J.R. Astro Soc.
Schaefer et. al 1993 “Records of young Moon sightings” Q.J.R. Astr. Soc. (v.34:pp.53-56)
Schaefer, B. E. 1993 “Astronomy and the Limits of Vision” Vistas of Astronomy (v.36,pp.
311-361)
Schaefer, Bradley E. 1996. Lunar Crescent Visibility. Q.J.R. Astro Soc.
Taqweem min 1409 hatta 1440 1408 Madina al-Malik Abd-Aziz lil-Ulum wa al-Taqniya
Riyadh
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Technical Standards for a Lunar Calendar
• The only way to build a workable global Hijri calendar
is to fix:
• A fixed Lunar dateline
• A standard method to calculate the start/end of
every lunar month at the lunar dateline
Social Standards for a Lunar Calendar
• Compliant with Islamic law
• Predictable and computable
• Easily observed
• Easily verifiable
• Easily understood
• Sensible enough to be followed all over the world
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Lunar Dateline
• Why International
Dateline (Solar)?
Two ships only 50 yards apart on
the two sides of IDL have
different dates
Proposed Lunar
International Dateline
• Why International Lunar
Date Line?
For fixed Hijri dates
• Why ILDL cannot be at
Makkah?
Regions east of Makkah even Taif
would have a different date
• Islamic date/day (from
local sunset)
• Global Islamic date from
180E (ILDL)
• The moon will be visible
somewhere around 180E
but not everywhere the
same evening
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Monday Sunday
180 E
180 W
International Dateline (Solar)
Global Lunar Islamic Calendar
Saudi dates for 1427-1435 (Moonset after the sunset in Makka)
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Global Lunar Calendar (Based on Visibility Around 180E)
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Islamic
Computational
Astronomical
Network
(ICAN)
ICAN
- Hijri calendars
- Global Prayers
schedules
- Global Qibla
directions
- Misc.
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Committee for Crescent Observations Intl (CFCO)
The Committee for Crescent Observation International (CFCO) is now part of ICAN,
an independent group of experts in the astronomy of moon’s visibility, and lunar
Islamic calendar. CFCO have been helping the Muslims all over the world since
1978 by accurately predicting the moon’s earliest visibility in the USA and other
regions of the world. We provide the ‘Dual solar/lunar dates’ calendar, and the data
to observe the crescent moon (Hilal) for any place.
CFCO helps Muslims fast and celebrate Eidain on correct dates
CFCO experts makes sure that the Ramadan and Eidain dates are fixed according to
the observable Hilal of the Qur’an and the Sunnah. We collect sighting claims from
all over the world each month, evaluate them by set visibility standards, and
publish our findings regularly.
CFCO’s criterion is the “earliest verifiable visibility of the crescent moon
somewhere (in North America)”.
Islamic day/date/month begins from a clearly “visible” crescent moon after sunset on
day 29 or day 30 of the lunation. If a moon is not seen consistently then odd
claims do not fulfill Shariah requirements of “Ghalabat-az-Zann” (overwhelming
probability) for Ramadan and “Ghalabatal-yaqeen” (near certainty) for Eidain.
How to be part of
CFCO?
Support CFCO
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Summary of Explanation
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This is about making a calendar – you can make one using the sun or the moon
People have used different methods to make either calendar for thousands of years
A lunar calendar works the following way: show with pictures
It used to be that you couldn’t exactly predict when it can be seen, now you can
Before modern telecommunications, people used to observe their lunar calendars in a local fashion, and it was not
possible to coordinate between countries and continents
Now we have a challenge: TO OBSERVE ONE GLOBAL LUNAR CALENDAR STANDARD
This standard must be: easily observed, easily verifiable, easily understood, and sensible enough that it can be
followed all over the world
There are two parts to an Islamic lunar calendar: how the moon behaves, and how people on the ground organize
their calendar based on its movements
The movement of the moon can be tracked scientifically, and through the use of computers we can predict this
That is the easy part
The tricky part is how people actually observe it on earth –
– there is the issue of how old a moon has to be before the human eye can see it,
– Where the sky is clear, some people will see it and some people will not
– Where it is cloudy, no one will see it
– We can now predict where it will be seen, and when
First big challenge: agreeing that we can predict when and where the moon is sighted (and this should always be
verified by eyesight, this is not just a computer model)
Second big challenge: making a calendar out of this
– Once you have a set of lunar times, to build a workable calendar you need:
• A standard dateline
• A standard method to calculate the start/end of the month
• A method to make the calendar consistent and useful
visit www.islamicmoon.com
5 Ways to a Great Presentation
Communication is very important in today’s world. What and how we deliver our
information can be the difference between success and failure. Here are few tips that
guarantee a great presentation.
1. SLOW DOWN: Speaking quickly means sacrificing clarity and may turn off your
listeners. Make good eye contact, breath more frequently and pause between new
ideas.
2. ORGANIZE your information: Tell your audience what you’re going to tell them.
Discuss your ideas. Talking about your ideas help you chose appropriate medium.
3. RECOGNOZE your limitations: You will never deliver everything you know. We
assimilate only 3 to 5 points of new information during a presentation. Be selective
of your information based on your audience and their needs.
4. PREPARE and PRACTICE: Outline your information, and practice the sequence
within the time limits. The words you speak in your head sound quite different when
you speak them loud. Discuss the logic behind your ideas.
5. BE Yourself: Don’t try to be or say what someone else wants you to be or hear,
regardless of the truth. Bring your unique qualities to your presentation.
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QUESTION AND ANSWER
SESSION
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