Institute for Islamic Services

As most of us are aware the Muslim Ummah is split into many groups and it is a great tragedy that Muslims are unable to get together even on the occasion of Eid. In the UK we have seen the most confusion where in the last few years we have seen Ramadhan and Eid being celebrated by different Mosques on different days. So which Mosques and Ulamaa (scholars) are guiding the Muslims correctly and what is the solution?

There are three main groups and opinions; 1.Those who ‘blindly’ follow Saudi Arabia, 2.Those who follow the concept of the birth of the new moon and 3.Those who follow the concept of the sighting/visibility of the new moon.

The correct method is by sighting the moon/crescent i.e. the visible new moon and this is practiced by the mass majority of Muslims all over the world and has been since 1400 years, from when The Prophet (Peace be upon him and his Family) himself established the new month in this way. The reason being is that Allah Ta’la commands the law to us in the Holy Qur’an:

“So he who from amongst you should witness the month should fast it” (Surah al-Baqarah, 185).The term witnessed is used meaning we must sight the moon.

The Islamic Law states if one person (two for Eid) sees the new moon then begin the new month. This is the Sunnah The Prophet left for us and we should not ignorantly jump to other methods.

In the UK we have seen that some people follow the Saudi ‘Royal’ family and announce the beginning of Ramadhan and Eid according to them. Islamically this is incorrect for the most important reason that all the evidences clearly state we begin Ramadhan and Eid according to the sighting and visibility of the new moon, not Saudi Arabia. There is not one piece of evidence in the Qur’an or the Hadith or any Islamic book to say we must follow Saudi Arabia, not even in any book published or approved by The Saudi Government. If there is, where is it written?

This problem only exists in the UK and some other countries in Europe. All other Muslim countries do not follow Saudi Arabia but have their own independent moon sighting committees’ who announce Ramadhan and Eid. Are the rest of the World’s Ulamaa wrong and don’t they know how to start the month? Most of the confusion here is caused by those Ulamaa and Mosques who blindly follow Saudi Arabia for political and financial reasons such as Regent’s Park Mosque who some people regard as a central Mosque. There are also other small Mosques who follow Saudi Arabia no matter what the status of the moon, disregarding The Qur’an and The Hadith

We also ask such groups that say not even 1000 years, not even a 100 years, but say 50 years ago how did people all over the world know that Saudi Arabia have announced Eid, What have Muslims all over the world been doing since and have they been wrong for 1400 years?

There can be no greater humiliation for those Ulamaa than the Saudi scholars actually saying themselves not to follow them. When the Permanent Committee for Fataawa were asked that should we begin Ramadhan and Eid when Saudia Arabia do? They stated in their public fatwa (legal verdict) that we should not follow Saudi Arabia and that everyone should begin the new month by sighting the new moon in their country. (Fatawah Islamia, Vol. 2, p113). In the same fatwa they included a reference of their Shaykh-ul-Islam ‘Ibn Thaymiyyah’ stating we should do Eid according to our own country. You should ask those groups why do they follow the Saudi ‘monarchy’. What is the reason?

The Sky is not clear so it is not possible to see the moon with the naked eye.

Particularly in the UK, it is not usually possible to see the moon with the naked eye. The objective and the intention is to start the new month and have the most accurate Islamic calendar possible and the Ulamaa have decided that it is beneficial to use astronomical calculations from The Observatory. It is logic and common sense that Islam allows us to use science and Allah Ta’la says “The Sun and moon follow course exactly”; He also said, “So that you may know the count of years and calculations”. It may be difficult to comprehend today but it was a Muslim scientist named al-Beruni who actually found and started the first observatory. It is not just recently that Ulamaa have acknowledged the Observatory, but leading scholars from the older times such as Imam Sha’fi, Imam As-Subki, Imam Ibn-e-Daqeeq Al’eed and others acknowledged astronomical calculations on this matter. Another important note is that the Ulamaa have personally gone to the observatory’s themselves before making use of them and it is also confirmed that since in use their information has been correct. All Mosques across the UK rely on the observatory for prayer times so for anyone who objects we ask why do they use such calculations for their prayer times? As Muslims we must not remain blind from the knowledge and existence of science, mathematics and other uloom which Allah has given us. Instead we should be using this to prove the truth of our Religion and for the benefit of Muslims to establish the truth and justice, in the way Allah and His Rasool please.

In an authentic Hadith The Prophet (Pbuh) said that the month has either 29 or 30 days and told us this 1400 years ago without the use of any astronomical information or observatory and this is also a challenge to the world’s scientist or anyone who denies The Prophet (Pbuh) had such knowledge to prove even 28 or 31 days in an Islamic month. The Holy Prophet (Pbuh) said:

“And if you see it then fast, and if you see it then break your fast. And if the clouds block then complete the count of 30 days of Sha’baan” (Bukhari Shareef, Muslim Shareef and others)

Islam is a clear and simple religion and a simple method is just to complete 30 days without all the complications. There are those who baselessly argue that at least if the moon cannot be sighted we should follow Saudi Arabia. Why? and even the Saudi Ulemaa said the same in their fatwa; to complete 30 days and they included the same Hadith. (Fataawa Ramadhan - Volume 1, page 56.) Again there is no mention of following Saudi Arabia.

Another misconception that is important to discuss is the difference between the new moon being born and the new moon being visible. When using astronomical data from the observatory we have seen some groups particularly in Birmingham follow the birth of the new moon, and they have linked with groups who follow Saudi Arabia who find this baseless argument go in their favour as their Eid is usually 1 day earlier. The birth and visibility are two very different factors because the new moon is not visible until its age is at least 20 hours and in many cases even 50 hours after birth (usually when the angle between moon-earth-sun is 12 degrees). When following the observatory we must follow the ‘possibility of visibility’, not the birth.

It is said in The Holy Qur’an “They ask you about the crescent, say these are signs to mark fixed periods of time for mankind and for the pilgrimage (Surah al-Baqarah, 189) In the verse it does not say ‘Mahaaq’ (new born moon), but it says ‘Hilaal’ meaning that new moon which is visible. According to the Quran and the Hadith The Mosques should announce Ramadhan and Eid according to the possibility of visibility of the new moon.

In the time of the Sihaba (RA), it is obvious they followed the moon which was visible and not that which was invisible for the basic reason it can not be seen and its initial birth is only told by observatories.

This year Eid-ul-Fitr should be celebrated on Friday 6th December, Insh’Allah. This is because The moon will not be visible anywhere in the world on Wednesday 4th December, the first moment the moon will be become visible is on Thursday 5th December. Also The Hadith based on completing 30 days, further proves Eid to be on Friday. All evidences show Eid to be on Friday and not on any other day. If the Saudi Government and its followers in The UK announce Eid to be celebrated on Thursday, this is totally unIslamic and is against the teachings of the Qur’an and the Hadith; according to the visibility of the moon and also the completing of 30 days, they have only completed 29 days. We ask such Ulamaa not to sell their Imaan to the Saudi’s and have some fear of Allah. They are supposed to follow the Shariah law and teach it, yet they are speaking totally against it. The Muslim community in the UK is requested to follow the right path, to save and protect their worship, and reject all non-Islamic formulas and decisions. When you ask why do those Ulamaa do all this when they know the law, all we can say is that one day they have to answer to Allah Ta’la.

Why is Saudi Arabia announcing Eid earlier than every other country in the world?

It may come as a surprise to some but for people who have an idea about The Saudi ‘Royal’ Family will not find it difficult to understand that in most cases Eid is done on the wrong day in Saudi Arabia. The following few paragraphs will prove by common sense and facts that Saudi Arabia, again this year will not be doing Eid on the correct day.

We have seen in the past that no other country or observatory in the world has said that the moon was visible and for some reason Saudi Arabia have announced that they have.
It is a matter of basic science and most people know that the moon rises from the west (the sun rises from the east) and for Saudi Arabia to see the moon it must have been seen by a country which is more west in order for Saudi Arabia to see the moon. Take for example this year if Saudi Arabia has announced that Eid will be on Thursday 5th December, no country west of Saudi Arabia will be able to see the moon on Wednesday 4th December for them to do Eid the following day on Thursday 5th December. So how is it possible that Saudi Arabia will be able to see the new moon?

The initial problem is that Saudi Arabia use a pre-calculated 30 year calendar which is based on the moon that is ‘invisible’. For two decades of monitoring the Saudi announcements by observatories and seeing the relevant print-outs it further proves they are starting holy events such as Eid according to the birth of the new moon, not the visibility. The initial problem was found when scholars from the UK visited Cambridge University and were told by Dr Yallop that the Saudi authorities requested a 30 year calendar based on the birth of the moon, and they still announce the Ramadhan and Eid according to that. Anyone can have a look at any Saudi calendar and see, even when they say they have been looking for the moon they still do Eid according to that 30 year calendar no matter what the status of the moon is. When checking the dates, one will find previous Holy months began by following the birth of the new moon, not the new visible moon.

If we look into the past announcements of The Saudi Regime it becomes very clear that they are announcing the beginning of Ramadhan and Eid on the wrong day, and it is easily possible to prove and refute each one. If we just take a recent example; on Thul Hijja 1422 AH / February 13th 2002,
The Saudi Supreme Court announced that the month of Thul Hijja (month of Hajj) will begin the next day (13th February), this is because they say that eyewitness testimonies saw the moon. However the moon could not be seen in Saudi Arabia on that 12th February as told by photographic evidence (taken afterwards) and various other Arab sources.
Along with the photographic evidence there are many statements by Arab authorities to further prove they began the month on the wrong day. Regrading this date The Arab Union for Astronomy and Space Sciences (AUASS) in their official statement by Mohammad Shawkat Odeh said “the crescent cannot be seen from nearly any region on Earth” and they further said “If the sighting of the crescent is what is necessary for beginning the month Thul Hijjah, then the first day of the month Thul Hijjah will have to be on Thursday, 14 February”. Also a statement from the Jordan Astronomical Society is very conclusive and leaves no doubt that Saudi Arabia announce the new months on the wrong day:

“It was not possible to see the crescent on Tuesday from nearly everywhere in the world, and this was confirmed by ICOP members who observed the crescent on Tuesday, where the crescent was not visible on that day from any country including USA, which is at the most western part of the world, that means if the crescent were to be seen on Tuesday from ONLY one country, then this country should be USA! Nevertheless, and despite all the scientific facts, and apart of the impossibility of seeing the crescent on Tuesday from Saudi, Saudi has declared that the crescent was seen by several persons from different parts in Saudi! Anyhow, this is not a new thing, Saudi had declared the same for Ramadan 1422 AH, but what the ordinary persons might not know is that the reports from the six official Saudi committees for crescent observation confirmed that no one saw the crescent on 29 Sha`ban. Nevertheless, these reports from the six official committees were rejected, and they just accept the claim of seeing the crescent from any person. (http://www.jas.org.jo/hej22.html#saudi)

Regarding an earlier moon sighting, a report from Salman Zafar Shaikh, a traveller with the 6 official committees for Saudi Arabian moon sighting said that, “I had gone with the Makkah committee. Neither we, nor the other 5 committees sighted the Hilal. But Eid was declared for Friday, January 7, 2000. (In fact moonset was before sunset in Makkah for Thursday evening). Later, an article in the locally published "Arab News" dated February 11, 2000 admitted that a mistake was made in the Eid ul Fitr date decision.” There are numerous other statements of this kind from other Arab countries too in relation to various other moon sightings but lack of space prevents us from reproducing them here. However the statements we have included should suffice for any intelligent and fair reader.

A very important note is that, the Ulamaa have said that because the people in Saudi Arabia have no choice under the current dictatorship so their Eid is accepted; also the same applies for the pilgrims.

One may question why would Saudi Arabia do Eid on the wrong day and why don’t they just change their pre-calculated dates. The problem is that they have an economic system based on those dates and also the fact they have strong political, economical and financial ties particularly with the USA and Israel. Even today the US army patrols the holy lands. In the world of economics today, we know what affect a minor decision can have or even a few hours, on September the 11th it took three hours for the US economy to collapse, what about a full day? Politics and money is being put before Islam.

The reason why The JAMA’AT-E-AHL-E-SUNNAT UK AND EUROPE and The SUNNI SOCIETY undertook the responsibility of producing this leaflet was because of how much confusion there is within the UK and people are ignorantly using non-Islamic methods. We must realise how important this matter actually is, as it is a matter of our own worship for which we are responsible for. We have shown the correct method based on the Qur’an and Sunnah and logic that our Holy books provide, in order to facilitate the possibility of Muslims in the UK doing Eid together and thus increasing Muslim unity. We would be grateful if you contact us regarding this leaflet or if we can help further in anyway.

Produced in association with MARKAZI JAMA’AT-E-AHL-E-SUNNAT UK & EUROPE (MANCHESTER BRANCH) and SIRAT UL MUSLIMIN.

The following text should accompany the image: Eid-al-Fitr: The moon's conjunction is on Wednesday, December 4, 2002 at 7:34 UT, i.e. 2:34 am Eastern Standard Time - 11:34 pm Pacific Standard Time on Dec 3. On December 4, the moon cannot be seen in Norway. Acknowledgement This article would not have been possible without the extensive research and work underaken for it by Brother Mustafa Qadiri-Jilani who was the main author and I just a co-author. I gratefully acknowledge his permission for me to publish it on Chowk.

A study of science of moon-sighting can clarify lots of misconceptions and wrong perceptions.

Most people associate visibility with the age of the moon. Age of the moon is simply the time lapsed since new moon. It can give a rough approximation for visibility. The visibility depends upon the angular separation of the moon from the sun seen from the earth. As the time passes from the instant of new moon, the angular separation between the sun and the moon increases. This angular separation reflects sun's light to earth. Until this angle becomes 7 degrees, no light of sun reflected by the moon can come to the earth, because of the mountains on the surface of the moon that block the sun light (Danjon 1932). This angle must be about 10-12 degrees from the sun's light to reflect from the moon making a thin crescent that can be sighted.

Another important factor is the moon's altitude above horizon. If the crescent thickness is sufficient, but it is not above horizon, then it can not be seen. This happens in the month of September and October in USA, when the moon is in the southern hemisphere, therefore, it can not be seen from northern hemisphere. The moon within the altitude of 10 degrees at sunset is usually not visible.

It is also a scientific fact that, if the moon is visible anywhere on the globe, it would be more easily visible on all places west of it. On the contrary, we hear the news of moon-sighting in Middle East, and on the same evening, here in North America several hours later, it is not visible despite clear horizons. This clearly tells us that what was seen in Middle East could not have been the moon.

Muslim astronomers in this age of technology are now in a position to calculate the dates for possible/impossible moon-sighting. So the validity of sighting claims can be easily verified for authentic moon-sighting. To start an Islamic month correctly, we must examine sighting claims in light of knowledge that Allah (swt) has given us. Let us pray to Allah (swt) to open our hearts and minds to understand these facts about moon-sighting.

However, there are several misconceptions about moon-sighting. The same are discussed below:

It is very possible that the 30th day moon of one month is about the same thickness as 29th day moon of another month. The moon revolves around the earth in an elliptical orbit, therefore, sometimes it is closer to the earth and sometimes it is farther from the earth. If the moon is 20 hours old on 29th day of one month when it is closer to the earth, it may look about the same size as, when it is 25 hours old on the 30th day of another month and is farther from earth.

Misconception 2: 29th day moon sets in a short time while 30th day moon remains longer on the horizon.

The moon above the horizon an hour before setting travels down to horizon line along a path whose inclination depends upon the latitude of the observer. A vertically downward path would be an Equator, and a 45 degrees slope at 45 degree latitude. The moon that is 10 degrees above horizon at Equator, would set quicker than a moon that is 10 degrees above horizon at a latitude of 45 degrees. Therefore, it is not correct to say that the 30th day moon remains longer on the horizon. Some months it may be, but not always.

Misconception 3: If the moon is thick and remains on the horizon a long time, it must be the 2nd day moon.

This is very common argument that we hear repeatedly, but has no truth in it. If on the 29th day, the moon at sunset is 18 hours old and is higher above the glare of the sun, it may be visible on that day and will appear to be very thin. However, if the 18 hours old moon on the 29th day is very low on the horizon, it would not be visible on that day, then on the 30th day it would be 42 hours old and quite thick, and remains above the horizon a long time, but it was not visible the day before.

By this sentence, people think that the far side of the moon is dark side of the moon, and that dark side faces us at New-moon day. That is not the case. The same side of the moon always faces the earth, sometimes illuminated, and sometimes dark. The moon takes 27 days, 7 hours and 43 minutes to spin, or rotate, once on its axis. It takes the same amount of time to orbit the earth. The combination of the two motions keeps the same side of the moon facing the earth. To us on earth, the moon is fully illuminated at full moon, completely dark at new moon, and partially lit in between.

Three consecutive months of 30 days are very possible and are not uncommon. In fact even four consecutive months of 30 days is possible, but rare. This is mainly due to considering the whole USA as one (Matla') horizon. Because of the elliptical orbit of the moon, two consecutive months of 30 days are quite common. In the third month, on the 30th day of previous month, sometimes the moon is only sighted on west coast, because for east coast it may have been 29th day from the actual sighting in east coast. If that is the case then in fourth month the moon may take 29 or 30 days to be visible. In the latter case it would be four months in a row that make 30 days' month. The Committee for Crescent Observation, Ithaca NY has been keeping the records of sighting in North America for the last two decades, and confirms that three consecutive months of 29 days, and four consecutive months of 30 days has occurred several times in USA.

This is wrong too. Full moon is the instant of time when the moon crosses an imaginary line passing through the centers of the sun and earth. This could happen at any moment of day or night. Therefore, it is very possible that in one month the moon is full at 7:00 a.m. This moon would be 99% lit on the night before and becomes full in the morning, but decreases to 99% lit-up on the following night. Such a moon would appear as a full moon to an observer on both nights. These two nights could be 13th and 14th, or 14th and 15th depending upon the location on earth and the time of new moon birth.

Mr. Khalid Shaukat is a consultant to Fiqh Council of North America for moon-sighting and qibla direction issues. He is also a consultant to Islamic Shura Council of North America (that comprises of four major Islamic organizations; ISNA, ICNA, Ministry of W. Deen Mohammad, and Jamaat Community of Imam Jamil Al-Amin).

The Islamic calendar is based on lunar months, which begin when the thin crescent Moon is actually sighted in the western sky after sunset within a day or so after New Moon. The ancient Hebrew calendar was also based on actual lunar crescent sightings, although the modern Hebrew calendar is calculated.

The 12 months of the Islamic calendar are: Muharram, Safar, Rabi'a I, Rabi'a II, Jumada I, Jumada II, Rajab, Sha'ban, Ramadan, Shawwal, Dhu al-Q'adah, Dhu al-Hijjah. Since 12 lunar months are, on average, 11 days shorter than the (Gregorian) civil year, the Islamic year shifts earlier in each civil year by about this amount. The count of years for the Islamic calendar begins in 622 CE; specificaly, 1 Muharram 1 AH corresponds to 16 July 622 CE (Julian calendar).

A tabular Islamic calendar has been established for some non-religious purposes in which the lengths of the months alternate between 29 and 30 days; in leap years an extra day is added to the last month, Dhu al-Hijjah. This calendar consists of a 30-year cycle in which 11 of the 30 years are leap years. Civil dates corresponding to important Islamic dates in this tabular calendar are:

Islamic New Year 1425 - 2004 February 22
First day of Ramadan - 2004 October 15
Islamic New Year 1426 - 2005 February 10
First day of Ramadan - 2005 October 4
Islamic New Year 1427 - 2006 January 31
First day of Ramadan - 2006 September 24
Islamic New Year 1428 - 2007 January 20
First day of Ramadan - 2007 September 13

The Islamic dates begin at sunset on the previous evening and end at sunset on the date listed above. These dates may or may not correspond to the evenings on which the crescent Moon is first visible, and it is the visibility of the crescent Moon that determines when the religious observance begins. The Moon's visibility at these times varies with location; generally, the visibility increases to the west, and locations in the tropics are favored over those in middle or high latitudes.

The visibility of the lunar crescent as a function of the Moon's "age" - the time counted from New Moon - is obviously of great importance to Muslims. The date and time of each New Moon can be computed exactly (see, for example, Phases of the Moon in Data Services) but the time that the Moon first becomes visible after the New Moon depends on many factors and cannot be predicted with certainty. In the first two days after New Moon, the young crescent Moon appears very low in the western sky after sunset, and must be viewed through bright twilight. It sets shortly after sunset. The sighting of the lunar crescent within one day of New Moon is usually difficult. The crescent at this time is quite thin, has a low surface brightness, and can easily be lost in the twilight. Generally, the lunar crescent will become visible to suitably-located, experienced observers with good sky conditions about one day after New Moon. However, the time that the crescent actually becomes visible varies quite a bit from one month to another. The record for an early sighting of a lunar crescent, with a telescope, is 12.1 hours after New Moon; for naked-eye sightings, the record is 15.5 hours from New Moon. These are exceptional observations and crescent sightings this early in the lunar month should not be expected as the norm. For Islamic calendar purposes, the sighting must be made with the unaided eye.

Obviously, the visibility of the young lunar crescent depends on sky conditions and the location, experience, and preparation of the observer. Generally, low latitude and high altitude observers who know exactly where and when to look will be favored. For observers at mid-northern latitudes, months near the spring equinox are also favored, because the ecliptic makes a relatively steep angle to the western horizon at sunset during these months (tending to make the Moon's altitude greater).

If we ignore local conditions for the moment, and visualize the problem from outside the Earth's atmosphere, the size and brightness of the lunar crescent depend on only one astronomical quantity - the elongation of the Moon from the Sun, which is the apparent angular distance between their centers. For this reason the elongation has also been called the arc of light. If we know the value of the elongation at any instant, we can immediately compute the width of the crescent.

What is the value of the elongation when the Moon's age is one day? It varies, depending on several factors:

(1) The elongation at New Moon. The Moon can pass directly in front of the Sun at New Moon (when a solar eclipse will occur) or can pass as far as five degrees away. That is, the Moon can start the month with an elongation ranging from zero to five degrees. A minor complicating factor involves the definition of New Moon in the almanacs. Astronomical New Moon is defined to occur when the Sun and Moon have the same geocentric ecliptic longitude, which may not occur precisely when the Sun and Moon are closest together in the sky.

(2) The speed of the Moon in its orbit. The Moon's orbit is elliptical, and its speed is greatest when it is near perigee, least near apogee. If perigee occurs near New Moon, the Moon will appear to be moving away from the Sun in the sky at a greater than average rate.

(3) The distance of the Moon. Again, because of its elliptical orbit, the distance of the Moon varies, so even if the Moon moved with a constant speed, its angular motion as viewed from the Earth would be greater when the Moon is near perigee.

(4) The location of the observer. If the observer is located in the tropics such that the one-day-old-Moon is observed just before it sets, its elongation as seen by the observer will be about a degree less than that seen by a fictitious observer at the center of the Earth, which is the basis for most almanac calculations. This decrease in observed elongation is less for observers at middle or high latitudes (although other geometric factors are less favorable for these observers).

Factors (2) and (3) are linked by Kepler's second law, which predicts that the angular speed of the Moon as seen from the Earth will vary by about 22%. If we combine all these factors we find that geocentric elongation of the Moon from the Sun at an age of one day can vary between about 10 and 15 degrees.

This large range of possible elongations in the one-day-old Moon is critical, because at this time the width of the crescent is increasing with the square of the elongation, and the surface brightness of the crescent is also rapidly increasing. Some of the earliest reliable sightings of the crescent occur near elongations of around 10 degrees. Obviously, simply specifying the age of the Moon cannot tell the whole story. Of course, the elongation of the Moon does not tell the full story, either. But, of the two parameters, the elongation is a much more reliable parameter to use as a starting point in assessing the lunar crescent visibility at any given date and time.

The prediction of the first sighting of the early crescent Moon is an interesting problem because it simultaneously involves a number of highly non-linear effects. Stated in less technical language, a lot of things are changing very rapidly. Effects to be considered are the geometry of the Sun, Moon, and horizon; the width and surface brightness of the crescent; the absorption of the Moon's light and the scattering of the Sun's light in the Earth's atmosphere; and the physiology of human vision. The problem has a rich literature. Some modern astronomical references are:

Schaefer, B. E., 1988: "Visibility of the Lunar Crescent", Quarterly Journal of the Royal Astronomical Society, Vol. 29, pp. 511-523.

Schaefer, B. E., Ahmad, I. A., Doggett, L. E., 1993: "Records for Young Moon Sightings", Quarterly Journal of the Royal Astronomical Society, Vol. 34, pp. 53-56.

Ilyas, M., 1994: "Lunar Crescent Visibility Criterion and Islamic Calendar", Quarterly Journal of the Royal Astronomical Society, Vol. 35, pp. 425-461.

Doggett, L. E., Schaefer, B. E., 1994: "Lunar Crescent Visibility", Icarus, Vol. 107, pp. 388-403.

M. B. Pepin, 1996: "In Quest of the Youngest Moon", Sky & Telescope, December 1996, pp. 104-106.

Her Majesty's Nautical Almanac Office computes and distributes predictions of lunar crescent visibility. The Astronomical Calendar by Guy Ottewell (published annually by Furman University, Greenville, SC) includes good diagrams of the positions of young and old Moons during the year (drawn for the eastern U.S.) and an explanation of the factors affecting their visibility

Note: For Moon phase information specific to a particular date, see
   Dates of Primary Phases of the Moon,
   Complete Sun and Moon Data for One Day,
   Fraction of the Moon Illuminated, or
   What the Moon Looks Like Today
in Data Services.

From any location on the Earth, the Moon appears to be a circular disk which, at any specific time, is illuminated to some degree by direct sunlight. Like the Earth, the Moon is a sphere which is always half illuminated by the Sun, but as the Moon orbits the Earth we get to see more or less of the illuminated half. During each lunar orbit (a lunar month), we see the Moon's appearance change from not visibly illuminated through partially illuminated to fully illuminated, then back through partially illuminated to not illuminated again. Although this cycle is a continuous process, there are eight distinct, traditionally recognized stages, called phases. The phases designate both the degree to which the Moon is illuminated and the geometric appearance of the illuminated part. These phases of the Moon, in the sequence of their occurrence (starting from New Moon), are listed below.

Moon Phases (click to see large version)

	New Moon - The Moon's unilluminated side is facing the Earth. The Moon is not visible (except during a solar eclipse).
	Waxing Crescent - The Moon appears to be partly but less than one-half illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is increasing.
	First Quarter - One-half of the Moon appears to be illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is increasing.
	Waxing Gibbous - The Moon appears to be more than one-half but not fully illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is increasing.
	Full Moon - The Moon's illuminated side is facing the Earth. The Moon appears to be completely illuminated by direct sunlight.
	Waning Gibbous - The Moon appears to be more than one-half but not fully illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.
	Last Quarter - One-half of the Moon appears to be illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.
	Waning Crescent - The Moon appears to be partly but less than one-half illuminated by direct sunlight. The fraction of the Moon's disk that is illuminated is decreasing.

Following waning crescent is New Moon, beginning a repetition of the complete phase cycle of 29.5 days average duration. The time in days counted from the time of New Moon is called the Moon's "age". Each complete cycle of phases is called a "lunation".

Because the cycle of the phases is shorter than most calendar months, the phase of the Moon at the very beginning of the month usually repeats at the very end of the month. When there are two Full Moons in a month (which occurs, on average, every 2.7 years), the second one is called a "Blue Moon". See the article "Once in a Blue Moon" for the story of how the usage of this term has evolved (Ref: Philip Hiscock, Sky & Telescope, March 1999, pp. 52-55.).

The first time that the thin waxing crescent Moon is visible after New Moon (low in the evening sky just after sunset) marks the beginning of a month in the Islamic Calendar - see the FAQ Crescent Moon Visibility and the Islamic Calendar.

Although Full Moon occurs each month at a specific date and time, the Moon's disk may appear to be full for several nights in a row if it is clear. This is because the percentage of the Moon's disk that appears illuminated changes very slowly around the time of Full Moon (also around New Moon, but the Moon is not visible at all then). The Moon may appear 100% illuminated only on the night closest to the time of exact Full Moon, but on the night before and night after will appear 97-99% illuminated; most people would not notice the difference. Even two days from Full Moon the Moon's disk is 93-97% illuminated.

New Moon, First Quarter, Full Moon, and Last Quarter phases are considered to be primary phases and their dates and times are published in almanacs and on calendars. (Click here for a list.) The two crescent and two gibbous phases are intermediate phases, each of which lasts for about a week between the primary phases, during which time the exact fraction of the Moon's disk that is illuminated gradually changes.

The phases of the Moon are related to (actually, caused by) the relative positions of the Moon and Sun in the sky. For example, New Moon occurs when the Sun and Moon are quite close together in the sky. Full Moon occurs when the Sun and Moon are at nearly opposite positions in the sky - which is why a Full Moon rises about the time of sunset, and sets about the time of sunrise, for most places on Earth. First and Last Quarters occur when the Sun and Moon are about 90 degrees apart in the sky. In fact, the two "half Moon" phases are called First Quarter and Last Quarter because they occur when the Moon is, respectively, one- and three-quarters of the way around the sky (i.e., along its orbit) from New Moon.

The relationship of the Moon's phase to its angular distance in the sky from the Sun allows us to establish very exact definitions of when the primary phases occur, independent of how they appear. Technically, the phases New Moon, First Quarter, Full Moon, and Last Quarter are defined to occur when the excess of the apparent ecliptic (celestial) longitude of the Moon over that of the Sun is 0, 90, 180, and 270 degrees, respectively. These definitions are used when the dates and times of the phases are computed for almanacs, calendars, etc. Because the difference between the ecliptic longitudes of the Moon and Sun is a monotonically and rapidly increasing quantity, the dates and times of the phases of the Moon computed this way are instantaneous and well defined.

The percent of the Moon's surface illuminated is a more refined, quantitative description of the Moon's appearance than is the phase. Considering the Moon as a circular disk, the ratio of the area illuminated by direct sunlight to its total area is the fraction of the Moon's surface illuminated; multiplied by 100, it is the percent illuminated. At New Moon the percent illuminated is 0; at First and Last Quarters it is 50%; and at Full Moon it is 100%. During the crescent phases the percent illuminated is between 0 and 50% and during gibbous phases it is between 50% and 100%.

For practical purposes, phases of the Moon and the percent of the Moon illuminated are independent of the location on the Earth from where the Moon is observed. That is, all the phases occur at the same time regardless of the observer's position.

Phases of the Moon 2007 -2010

Young Crescent Visibility Predictions for 2005
(ISLAMIC 1425/1426)

Young Crescents
Because of the earth's motion around the sun, the sun appears to move along a path through the sky called the ecliptic. The sun's position on this path (measured from the point where it crosses the equator moving north) is the sun's celestial longitude. Each new astronomical lunar month (lunation) begins at the moment when the centre of the moon has the same celestial longitude as the centre of the sun, from the perspective of the centre of the earth (i.e. the moment hen the moon `passes" the sun). This is the moment of astronomical new moon. At this time the moon is always invisible from the earth. When the moon first becomes visible again (always more than half a day after astronomical new moon), observers see a young crescent moon. The distinction, popular with some crescent observers, between LOCAL NEW MOON (celestial longitudes of the moon and sun are the same from the observers location) and the standard astronomical new moon described above, is not important for our crescent tables. The age of the moon is a VERY poor way to estimate crescent visibility (unless combined with the time interval between sunset and moonset), and the altitudes and azimuths we use for estimating visibility (see below) are all calculated for the four specific locations given.

Note: Usually the moon does not have the same celestial latitude (distance north or south of the ecliptic) as the sun at the instant of new moon. If the celestial latitudes do happen to be nearly the same, the moon will pass in front of the sun as seen from parts of the earth's surface, causing an ECLIPSE. Usually the moon is "above" or "below" the sun at the time of new moon, and no eclipse occurs.

Predicting the Evening of First Visibility
From a study of the of the published literature, observations (from reliable sources) reported on the Internet, and our own visual observations, we have found that a simple set of rules based on the position of the crescent at sunset can reliably predict the visibility of the crescent under ideal viewing conditions (cloudless, clear air, etc.). Our standards are intentionally "optimistic," taking account of all reliable known sightings, and allow for the improved likelihood of seeing a marginal crescent using optical aid. Actual visibility will not be better than our predictions and it will normally be worse in mediocre conditions. Our rules for lunar crescent visibility are not intended for use at high latitudes (i.e. near the poles). To estimate crescent visibility for ideal conditions, we use the moon's position at sunset relative to the sun, the altitude/azimuth method. The moon's altitude is measured upward from the horizon to the bottom edge of the moon, and is 0 degrees at the horizon and 90 degrees overhead. The moon's azimuth difference is the difference between a compass bearing (direction) to the sunset point and to the point on the horizon directly below the moon. If the moon at sunset is directly above the sunset point, this quantity is 0 degrees. If the moon is directly above a point, say, 10 degrees north of the sunset then the azimuth difference is +10 degrees, and so forth. The further north or south of the sunset point the moon is at sunset, the lower the crescent moon can be and still become visible during the course of twilight. To make it clearer how we have used the available observations, we include two "Visibility Data" graphs. For each reported observation, a symbol on the graph indicates the showing the moon's sunset position and whether the young crescent was visible with the naked eye, with optical aid, or not at all. Successful sightings by naked-eye observers are represented by large filled circles; filled circles crossed by short horizontal lines represent more marginal sightings. Large open circles represent successful sightings by observers using telescopes or binoculars, where the moon was not visible with the naked eye. Large open circles crossed by short horizontal lines represent occasions when the crescent could be seen through a telescope, but not with the naked eye or with binoculars. Large 3-pointed symbols represent occasions when the moon was not visible with the naked eye or with optical aid; small 3-pointed symbols represent unsuccessful attempts to see the moon with the naked eye when optical aid was not employed.If the crescent moon at sunset has a large enough altitude such that the symbol plotted in the graph lies on or above the upper (i.e. solid) line, then we infer that visibility will be POSSIBLE. Any cloudiness, haziness, dust, etc. will drastically reduce the likelihood of seeing a young crescent, so one can never predict that visibility will be certain. If a particular crescent lies lower in the sky (and closer to the cutoff line), it will naturally be harder to see. (See Figure 1)

The sightings and nonsightings allow us to draw two lines in the graph. If the crescent moon is below the upper (solid) but above the lower (i.e. dashed) line, then we infer that visibility will be IMPROBABLE, by which we mean that seeing the crescent without a telescope or binoculars is exceedingly unlikely. Sighting the moon with optical aid may be possible if the crescent is near the upper altitude limit, but glimpsing it visually would be limited to observers in exceptional conditions with exceptional eyesight, if feasible at all. If the crescent at sunset is near the lower altitude limit, sighting the moon would be exceedingly unlikely even with optical aid. Crescent moons falling below the lower (dashed) line are considered to be genuinely IMPOSSIBLE to see according to the accumulated record of reasonably well-substantiated sightings and non-sightings. Observers should keep in mind that our limits are already very lenient and optimistic, and represent what may be possible for an experienced observer with excellent eyesight under excellent conditions.

Age of the Crescent
It is very popular to use the age of the moon or the time lag between the setting of the sun and the moon, to predict whether the young crescent will be visible, particularly as these numbers are easy to obtain. The second graph shows that the age alone cannot give a reliable prediction, despite the often heard claim that `The moon is X hours old so you must be able to see it." Even quite old crescents can remain invisible if the moon is low in the sky at sunset, well to the north or south of the sunset point. By the time the bright glare of western twilight has faded enough that visibility might be possible, such a crescent will have set. For this reason, age must be used with oonset lag time' (the difference between the times of sunset and moonset) to be useful at all. Since predictions are still somewhat less precise than with the altitude/azimuth method, our predictions are based on the latter. (See our website for more explanation). (See Figure 2)

3. CRESCENT VISIBILITY at Thil-Gijja, Muharram, Ramadaan and Shawwall
(for experienced observers with ideal weather conditions and good eyesight)

(All diagrams in this section generated using Dr. Monzur Ahmed's Mooncalc 6.0 software, with the SAAO visibility criteria).

THIL-GIJJA:
On the evening of 10 January, observers with good eyesight and perfect weather conditions might be able to see the crescent with a telescope from parts of the west coast of Chile. It will not be possible to see the crescent with the naked eye except from parts of the Pacific from the tropics southward. The crescent should be visible with the naked eye on the evening of 11 January from South America and North America, Africa, much of Europe (excluding northern Britain and Ireland, northern Germany, the Netherlands, Scandinavia, etc.), and from the Middle East. It will be visible from South and Southeast Asia and Australasia, but not from Korea, northern China, most of Japan or Siberia. (Figure 3) .

MUHARRAM:
On 9 February, the young crescent is potentially visible to the naked eye from virtually all of North and South America and Africa, and from southern Spain and Portugal and the southwestern parts of the Arabian peninsula, given ideal weather conditions. From parts of southern Europe, Turkey and the Middle East, as well as much of India and possibly Sumatra, it may be visible with optical aid. The moon should be easily visible on the evening of 10 February if the sky is clear. (Figure 4)

RAMADAAN:
On 3 October, the young crescent may be visible with optical aid from parts of the southern Pacific Ocean, but will be invisible elsewhere, including Africa, the Americas, the Middle East and Eurasia. On 4 October, the crescent may be visible with the naked eye from South America, from the southern half of North America, from Africa except north of the Sahara, from most of the Arabian peninsula, and from southern India, parts of Southeast Asia, most of Indonesia and Australasia. With well-aimed binoculars or a telescope, observers in Africa north of the Sahara, the northern Arabian peninsula, southern Iran, northern India and the remainder of Southeast Asia may be able to see the moon that evening if conditions are clear enough. From Europe and from most of Asia and from the northern parts of the Middle East, the crescent will not be visible until the evening of 5 October. This lunation is one where southern observers are strongly favoured. (Figure 5).

SHAWWALL:
On 2 November, the young crescent may be visible with the naked eye from South America (except the northeastern parts), and from parts of the southern Pacific. With ideal conditions and optical aid, the young crescent may also be visible from the rest of South America and Central America, from the South Atlantic and from the southwesternmost parts of South Africa, including Cape Town. The crescent will not be visible in the remainder of Africa, or in Eurasia (including the Middle East) or Australasia. On the evening of 3 November, the young crescent may be spotted with the naked eye from most of North and South America, from parts of southern Europe, from southern Turkey and most of the Middle East, from all of Africa, and from southern Asia and from Austrasia. From much of Europe and Asia, the crescent will only become visible on the evening of 4 November. (Figure 6)

THIL-GIJJA (2):
On the evening of 31 December, naked-eye observers with clear skies and clear western horizons have a good chance of seeing the young crescent from Mexico, Central and South America and the tropical and southern Pacific. Observers with well-aimed binoculars or telescopes may be able to see the moon from southern Africa and southern Madagascar, and from parts of West and Central Africa if conditions are ideal. There is an outside possibility that experienced observers with extremely sharp eyes might be able to see the crescent from Cape Town and other points on the west coast of South Africa if conditions are absolutely perfect. On the evening of 1 January, 2006, observers worldwide should be able to see the crescent if skies are clear, except in Scandinavia and other parts of northern Eurasia. (Figure 7)

How can this be possible? An extremely young crescent is difficult to see because it simply isn't bright enough to show up well against the bright twilight sky. The most marginal sightings we have detected from Cape Town were clear in binoculars, but to the naked eye hardly more than a rather shapeless, hardly perceptible brightening on one tiny piece of the sky, which the eye had to be staring directly at to notice. In this situation the eyes and the mind are "straining" to find something and can imagine seeing "something" which is mistakenly assumed to be the crescent.

Even in relatively good conditions, a low-contrast brightness or haziness structure is commonly present in the twilight sky. Aircraft trails, suspended objects, filamentary structure in distant clouds, banded structure in the twilight due to air layers with different properties etc. can give rise to the perception of "seeing something there." Many minutes of staring can produce fatigue, and there may be also a mental bias in favour of finding the crescent to achieve a "successful" outcome. Poorer observing conditions call for increased skepticism, but in practice we have seen remarkable flights of imagination - crescents at best marginally visible in ideal conditions, but somehow "seen" when the western sky was cloudy or hazy.

One must be quite realistic about the difference between good, basically clear conditions, and poor conditions where one hopes e.g. to find a lucky gap in a very messy sky. Likewise one must be hard-headed in distinguishing between whether you have DEFINITELY seen the crescent, on the one hand, or whether you have had no more than a fleeting impression of having momentarily glimpsed "something".

Well-known scientists have "seen" nonexistent canals on Mars and nonexistent markings on Venus, and crescent observers have reported seeing the crescent days before it was in the evening sky at all, or through murky "windows" in thick clouds. In one large-scale experiment in North America, about 1 in 7 reported sightings of the young crescent were clearly not real (moon not in sky at reported time, etc.).

One clue that a very marginal crescent sighting may be real is that the elongated bright patch which may be all the eye can detect of the crescent should be continuously visible for a minimum of several seconds at a time, and is seen repeatedly at a sky location which is consistent from one minute to the next. The shape of the brightening should be consistent with the moon-sun angle. If these tests are not met, the sighting should NOT BE ACCEPTED. Keep in mind that a careful, conservatively judged non-sighting with your best effort is very much more useful information than a "false positive" claim that can spread serious confusion. It should also be kept firmly in mind that a report from the northern hemisphere or from the Americas does not "validate" a report from southern Africa, or vice versa. Examination of our crescent visibility table or of the visibility maps for Thil-Gijja, Muharram, Ramadaan and Shawwall, will clearly show that visibility in one place does not necessarily imply visibility in another region - South Africans may see the moon a day later or a day earlier than people in the Middle East, and Latin Americans will quite frequently see the moon a day earlier than either. Above all, always bear in mind that self-deception is surprisingly easy when trying to detect something near the limits of perception.

www.islamservices.org

Phases of the Moon and Percent of the Moon Illuminated

Phases of the Moon 2007 -2010

Young Crescent Visibility Predictions for 2005
(ISLAMIC 1425/1426)

www.islamservices.org

Phases of the Moon and Percent of the Moon Illuminated

Phases of the Moon 2007 -2010

Young Crescent Visibility Predictions for 2005 (ISLAMIC 1425/1426)

Young Crescent Visibility Predictions for 2005
(ISLAMIC 1425/1426)