1. 27 th November 1999 Scientific Developments in Moon Sighting Presented By Aliyu Abubakar Aziz aaziz@compuserve.com Tel: 09-523 7199 Abuja Centre for Arabic Studies (ACAS) 3 rd Annual Ramadan Symposium

2. Scientific Developments in Moon Sighting2 Introduction When it comes to sighting the new crescent moon, Muslims in Nigeria are principally divided into two groups The first group would always claim to have sighted the crescent on the day of conjunction (i.e. the phase during Moon’s orbit, when the Moon, Earth and the Sun lie exactly at the same line, with the Moon in the middle). While the second group would claim that the Moon was seen at east that morning and therefore could not have been sighted on the same day at west in the evening. Introduction

3. Scientific Developments in Moon Sighting3 Introduction As a result of this, we always commence fasting of the month of Ramadan and celebrate Eid on two different days in the same town. The questions are: Are there any relationships between crescent sighting at west in the evenings and moon sighting at east in the morning hours of the same day? Are we living in an area with peculiar geographic conditions that allow us to be among the earliest observers of the crescent in the world? Does moon sighting have relationship with eclipses? Introduction

4. Scientific Developments in Moon Sighting4 Introduction This presentation will seek to answer these questions through the development of modern scientific criteria for sighting the new crescent moon in the light of Islamic Shariah. May Allah Guide us. Let us first see what Allah (swt) says about this subject: Introduction

5. Scientific Developments in Moon Sighting5 Introduction Surah Rahmaan 55, Ayah 5: “The Sun and Moon follow courses exactly computed” Surah Yunus 10, Ayah 5: “It is He who made the Sun a radiance and the Moon a light and determined its stations that you might know the number of years and reckoning of time” Surah Baqarah 2, Ayah 189: “They ask you about the crescent moons, say: they are signs to mark fixed periods of time for the people and for pilgrimage” Introduction

6. Scientific Developments in Moon Sighting6 Introduction These Ayaat are telling us that the Moon and Sun follow the decree of Allah (swt) and must be used for reckoning of months and calendar. Fortunately we now have Muslim astronomers who can predict, for many years in advance when and where the new crescent moon will first appear. Introduction

7. Scientific Developments in Moon Sighting7 Topics of Discussion  Basic Facts about the Moon  Science of Crescent Visibility  Methods of Sighting the Crescent  Misconceptions on Moon sighting  Actual Saudi Dating System  Expectations for this Ramadan  What’s Next  Conclusions Introduction

8. Scientific Developments in Moon Sighting8 The Moon The Moon The Moon is our companion in space, and stays together with us as we travel round the Sun. It is much nearer than any other natural body in the sky, which is why it appears so brilliant. This bleak, airless sphere is about 3,476 kilometers in diameter, and revolves around Earth at an average distance of some 384,400 kilometers, completing one revolution in about 27 days. The lunar orbit is an ellipse, not a true circle; so the distance of the Moon from the Earth changes. Basic Facts about the Moon

9. Scientific Developments in Moon Sighting9 The Moon The Moon Since the Moon rotates on its axis in the same time it takes to revolve around the Earth, the lunar hemisphere visible to us remains about the same. Basic Facts about the Moon

10. Scientific Developments in Moon Sighting10 The Light of the Moon Sunlight falls on the Moon as it does on Earth. What we call "moonlight" is simply sunlight which the Moon is reflecting toward Earth. Except during lunar eclipses, a full half of the Moon is always lighted by the Sun. But we see this full half only when Earth is between Sun and Moon - the phase called full Moon. When the Moon is not in line with Earth and Sun, we see only part of the lighted half. Basic Facts about the Moon

11. Scientific Developments in Moon Sighting11 The Lunar Phases The familiar lunar phases occur because the Moon does not always turn its daylight side toward the Earth. When it is almost between the Earth and the Sun, the Moon is new (1) and its dark (the side that is not receiving light) side is turned toward the Earth. It cannot then be seen unless the alignment is perfect enough to produce a solar eclipse. At 2 it is at half (first quarter); at 3 it is full; and at 4 it is at half once more (last quarter). Between half and full phases the Moon is "gibbous". See Figure 1.0 Basic Facts about the Moon

12. Scientific Developments in Moon Sighting12 The Lunar Phases 1 Earth 4 3 2 Sun’s rays Figure 1.0 Basic Facts about the Moon

13. Scientific Developments in Moon Sighting13 Lunation The Moon takes 27.3 days to move round the barycenter - the center of gravity of the Earth- Moon system, which lies within the Earth's globe. However, the Earth is moving round the Sun. The Moon is new at (a); when it has returned to (a), during the Earth's orbit of the Sun, it is still not lined up and must move on to (b) before it is new again. The "lunation", or interval between successive new moons, is therefore 29.5 days (29 days, 12 hours 44 minutes and 2.8 seconds), not 27.3. See Figure 2.0 Basic Facts about the Moon

14. Scientific Developments in Moon Sighting14 Lunation a a b Earth Sun Figure 2.0 Basic Facts about the Moon

15. Scientific Developments in Moon Sighting15 Lunar Eclipse An eclipse of the Moon occurs when the Moon passes into the cone of shadows cast by the Earth. If the Moon partially enters the cone there is a partial eclipse; if it wholly enters the cone the eclipse is total. Eclipses do not happen at every full Moon because the lunar orbit is appreciably inclined. Basic Facts about the Moon

16. Scientific Developments in Moon Sighting16 Lunar Eclipse Basic Facts about the Moon Sun Earth Moon Figure 3.0

17. Scientific Developments in Moon Sighting17 Solar Eclipse Eclipses of the Sun occur when the Earth, Moon and Sun are aligned. A total eclipse is seen at places along a narrow band, the path of totality. Over a wide area outside this band, a partial eclipse is seen. Unfortunately solar eclipses do not occur every month because the Moon's orbit is inclined to that of the Earth and, at most new Moons, the Moon passes either "above" or "below" the Sun in the sky, thereby avoiding eclipse. Basic Facts about the Moon

18. Scientific Developments in Moon Sighting18 Solar Eclipse Basic Facts about the Moon Sun Moon Shadow Zone Observer sees total eclipse Path of totality Area of partial eclipse Observer sees partial eclipse Earth Figure 4.0

19. Scientific Developments in Moon Sighting19 Crescent Moon Just after new Moon, a thin bright crescent is seen. The rest of the disk is faintly lighted. This faint light, called "the old Moon in the new Moon's arms" is light reflected from Earth to the Moon's dark side, and is known as earthshine. Basic Facts about the Moon

20. Scientific Developments in Moon Sighting20 Crescent Moon The Moon rises about 50 minutes later each night on the average, but the actual time from month to month varies considerably. For some evenings around full Moon near the autumnal equinox (about September 23) moonrise will be only about 20 minutes later each night, because the angle between ecliptic and horizon is then near the minimum. Thus we have moonlight in early evening longer than usual. This phase is called Harvest Moon. The next full phase after Harvest moon is known as Hunter's Moon. Basic Facts about the Moon

21. Scientific Developments in Moon Sighting21 Crescent Moon The lunar pathway stays near the ecliptic or path of the Sun. However, while the Sun rides high in summer and low in winter, the Moon rides low in summer and high in winter. At the full phase, the lunar disk may take odd shapes as it rises or sets, particularly when seen through a dense or smoky atmosphere. Sometimes reflection makes it look oval. Basic Facts about the Moon

22. Scientific Developments in Moon Sighting22 Science of Crescent Visibility The Moon orbits Earth once every 29.53 days (average of synodic month). Because of this revolution, phases of the Moon change as the Moon's position change relative to the Earth and the Sun. So, during the Moon's orbit, if the Moon, Earth and the Sun lie exactly at the same line and the Moon in the middle, the Sun will illuminate half of the Moon that faces it, and the other half which faces us, will be dark because it does not reflect rays of the Sun. Science of Crescent Visibility

23. Scientific Developments in Moon Sighting23 Science and Crescent Visibility At this point, the Moon is called Wane or New Moon (Astronomical New Moon not CRESCENT). After that, the Moon continues orbiting the Earth and begins to reflect a small amount of Sun's rays and now we see the Moon as a very small waxing crescent. Afterwards, it becomes first quarter, full Moon, last quarter, waning crescent and then wane again. Moon's age is measured from the moment of the wane (New Moon). We often say this Full Moon is 14 days old, which means that the number of days since the wane is 14. And we say this crescent is about 2-3 days old. Science of Crescent Visibility

24. Scientific Developments in Moon Sighting24 Science and Crescent Visibility But, did any one ask himself what is the minimum age of crescent that we can see? Generally, it is not likely to see a crescent that is less than 17 hours, i.e. if we want to observe the thin waxing crescent to determine the beginning of an Islamic month, the Moon should be in the wane phase (New Moon) 17 hours ago or more. But why?! Science of Crescent Visibility

25. Scientific Developments in Moon Sighting25 Science and Crescent Visibility The wane Moon (New Moon) is located exactly at the Sun's direction, so the Sun's glare will prevent us from seeing it, in addition, the percentage of the reflected rays out of the wane Moon (New Moon) is nearly equal to zero, and this percentage increases as the Moon's age increases. Thus, GENERALLY human eye can't detect any reflected rays from the Moon if the Moon's age is less than about 17 hours. Science of Crescent Visibility

26. Scientific Developments in Moon Sighting26 When to Locate the Waxing Crescent? The new waxing crescent is located near the Sun, so we shall wait until Sunset, because it is obviously not possible to observe the thin waxing crescent before Sunset. In addition, we must wait a reasonable time until the twilight decreases, i.e. until we can differentiate between Moon's light and twilight glare, a 10-minute period could be enough sometimes to detect the thin waxing crescent. Science of Crescent Visibility

27. Scientific Developments in Moon Sighting27 Where to Locate the Waxing Crescent? As mentioned above, the wane Moon (New Moon) is located exactly near the Sun. If we assume that the Moon will set when it is wane (New Moon), generally it will set along with the Sun, but we are looking for a new crescent, which means that it is still near the Sun. So, we must look at the west, a little bit over the Sunset point. Science of Crescent Visibility

28. Scientific Developments in Moon Sighting28 When the Waxing Crescent Sets? The Moon, like the Sun, rises from the East and sets after about 12 hours at the west (with exceptions at high-latitude areas), and since the waxing crescent lies near the Sun, it will set after the Sunset, and in its best cases, the new waxing crescent sets about one hour after the Sunset. Science of Crescent Visibility

29. Scientific Developments in Moon Sighting29 Are the 17 hours only, enough as a factor to determine the crescent visibility? Of course not. There are several factors that must be met in order to view the thin waxing crescent: Some of these factors are:- The angular distance between the centers of Sun and Moon. The crescent's altitude. The Moon's staying (the interval between the Sunset and the Moon set). The azimuth difference between the Sun and the Moon. Science of Crescent Visibility

30. Scientific Developments in Moon Sighting30 What's the Meaning of Astronomical Calculations of the Crescent? Most people think that the astronomical calculations mean absolute determination of crescent visibility, but this is not true, the astronomical calculations include the following: 1. The time of the wane Moon (New Moon) must be determined, and this time is accurately calculated. For sure there is no chance for any error. 2. Some of the above factors are determined. Such as the Moon's altitude, the angular distance between the centers of the Sun and the Moon at the Sunset, Sunset time and the Moon set time, Moon's staying period,...etc. Science of Crescent Visibility

31. Scientific Developments in Moon Sighting31 What's the Meaning of Astronomical Calculations of the Crescent? 3. The results of the above calculations must be compared with crescent visibility conditions in the previous years, and with the accurate practical and international observations. Note: It is absolutely impossible to see the thin waxing crescent after sunset if the Moon didn't reach the Wane phase (New Moon) yet. How can we see the new crescent if it is not wane yet?!. " Who claims that he viewed the thin waxing crescent before the New Moon instant, is like the one who claims that he saw the Sun before dawn, or he saw the baby before delivery", ancients said. Science of Crescent Visibility

32. Scientific Developments in Moon Sighting32 Guidelines To locate the thin waxing crescent, we have to start looking for it after a while of the sunset at the West, a little bit above the point at which the Sun sets, in its best cases, crescent sets about one hour after Sunset. The following are the guidelines to prepare individuals for crescent moon sighting: Methods of Sighting the Crescent

33. Scientific Developments in Moon Sighting33 Guidelines 1. On an evening previous to the Moon Sighting evening, it is advisable to FIND A PLACE WITH A CLEAR WESTERN HORIZON (i.e without any buildings or trees obstructing the place where the sun sets, on the western horizon). 2. It should be noted that the actual PLACE OF THE SETTING OF THE SUN varies with the seasons. In the northern hemisphere, the sun sets to the north of west during the summer with the extreme north setting on the summer solstice (June 22). The sun sets due west on the autumnal equinox (Sept 22). The sun again sets due west on the spring equinox (March 21). Methods of Sighting the Crescent

34. Scientific Developments in Moon Sighting34 Guidelines 3. Observe and note down the approximate angle of inclination of the PATH OF THE SUN while it is setting. This inclination of the path of the setting sun from the vertical is nearly equal to the latitude of observing location. 4. TO SEEK THE CRESCENT MOON. In order to obtain an idea as to approximately where to look, the following information on LUNAL ORBIT is useful: Methods of Sighting the Crescent

35. Scientific Developments in Moon Sighting35 Guidelines To seek the crescent moon… i. The PATH OF THE CRESCENT MOON while it is setting will be nearly parallel to the path of the setting Sun. The path of the Moon will be CLOSE to the path of setting Sun, being at a maximum of about 5 degrees (usually it is less than the +/-5 deg) ‘above’ or ‘below’ the path of the sun, when it is observed from the surface of the earth. Methods of Sighting the Crescent

36. Scientific Developments in Moon Sighting36 Guidelines To seek the crescent moon… ii. The CRESCENT MOON will also be TRAILING the SUN by about 5 to 20 degrees, for a particular observing point. The earliest sightings in the world would have the moon trailing the sun by the least angle. The Trailing angle of the Moon from the Sun can be estimated from the Orbital details and the location of the observer. Methods of Sighting the Crescent

37. Scientific Developments in Moon Sighting37 Guidelines To seek the crescent moon… iii. The DURATION OF THE FIRST SIGHTING of very young moons may begin as early as 10 minutes after the sun has set (to allow the twilight to reduce in spectral intensity) with the first sightings being usually before 20 minutes after sunset and the sighting could continue for about 40 to 90 or more minutes after sunset. The sighting would finally be ‘fading’ when the crescent is a few degrees above the horizon. Methods of Sighting the Crescent

38. Scientific Developments in Moon Sighting38 Guidelines To seek the crescent moon… iv. THE HORNS OF THE CRESCENT MOON (i.e. the ends of the approximately less than semi- circle arc of the Crescent) will always point in a direction approximately opposite to the location of the sun, the sun already being below the horizon. Methods of Sighting the Crescent

39. Scientific Developments in Moon Sighting39 Criteria for Crescents Visibility 1. Moon's age is equal to, or more than, 17 hours. 2. The angular distance between the Sun's center and the Moon's center at Sunset is equal to, or more than, 7 degrees. 3. The Moon's altitude at Sunset is equal to, or more than, 4 degrees. 4. The interval between Sunset and Moon set is equal to, or more than, 12 minutes. Methods of Sighting the Crescent

40. Scientific Developments in Moon Sighting40 Criteria for Crescents Visibility If the crescent satisfies these conditions, it is expected to be seen from a highly-elevated and clear area. Knowing that an excess of one of these factors may compensate for the lack of another, for instance, if the angular distance between the Moon and the Sun is 10 degrees and the Moon's altitude is just two degrees, then the big angular distance may compensate for the small value of the Moon's altitude. Methods of Sighting the Crescent

41. Scientific Developments in Moon Sighting41 Methods of Starting Islamic Months in Different Countries There is no unique method adopted by all the Islamic countries to start the Islamic months. There are many methods spread all over the Islamic World, some of them are:- 1. If the Wane Phase (New Moon) occurs before midnight, then the next day is the first day of the Islamic Month. This method is adopted in astronomical books and magazines and some Islamic countries. 2. If the Wane Phase (New Moon) occurs before Sunset, then the next day is the first day of the month. Since the Islamic day starts at Sunset not at midnight. Methods of Sighting the Crescent

42. Scientific Developments in Moon Sighting42 Methods of Starting Islamic Months in Different Countries 3. Some countries adopt specific criteria, such as the Moon's age, altitude, the interval between Sunset and Moon set,...etc., and if the Moon fulfills these criteria at Sunset, then the following day is the first day of the Islamic Month. Methods of Sighting the Crescent

43. Scientific Developments in Moon Sighting43 Methods of Starting Islamic Months in Different Countries 4. Some countries adopt the actual sighting of the crescent with the assistance of astronomical calculations. This is the most reliable and accepted method among people and scientists, as well as among most of scientists of Islamic Shari'a nowadays. Adoption of this method follows Prophet Mohammad’s “Pbuh" order to us not to start the month except when we view the crescent, thus it must be seen, and we use astronomical calculations in order to know where and when to observe, as well as the probability of observing the crescent, since sometimes it would be useless to observe the crescent if the calculations show that there is no crescent after Sunset ! Methods of Sighting the Crescent

44. Scientific Developments in Moon Sighting44 Methods of Starting Islamic Months in Different Countries 5. Other countries adopt several different ways, some of them make the month 29 and 30 days alternately, others make Ramadan either 29 or 30 days always, and finally some countries don't adopt any specific Methods of Sighting the Crescent

45. Scientific Developments in Moon Sighting45 Main Factors for Crescent Visibility 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. This may be explained better with the help of the following figure. Methods of Sighting the Crescent

46. Scientific Developments in Moon Sighting46 Main Factors for Crescent Visibility Methods of Sighting the Crescent Sun Crescent Moon Earth New Moon Full Moon Figure 5.0

47. Scientific Developments in Moon Sighting47 Main Factors for Crescent Visibility Figure 5.0 shows a space view of sun, moon and earth. The earth revolves around the sun in an elliptical orbit, with the sun off-center, and the moon revolves around the earth in a similar way. When the new moon occurs, the sun, moon, and earth come in line as shown, and no light of the sun falling on the moon can come to the earth, so it is a dark or invisible moon. Methods of Sighting the Crescent

48. Scientific Developments in Moon Sighting48 Main Factors for Crescent Visibility About 18-24 hours after the new moon, the moon moves away from the line of earth and sun, to its new location as shown by the location of the crescent moon. Now the sun and moon have separated from the same line. The angle subtended by sun, earth, and moon is the “angular separation”. This angular separation causes the crescent to form. Methods of Sighting the Crescent

49. Scientific Developments in Moon Sighting49 Main Factors for Crescent Visibility 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. 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. Sometimes this crescent is very thin and very low on the horizon, so it can not be seen as it disappears in the glare of the sun, and therefore is not visible, even though it may remain above horizon for 20-30 minutes after sunset. Methods of Sighting the Crescent

50. Scientific Developments in Moon Sighting50 Main Factors for Crescent Visibility 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 northern hemisphere, when the moon is in the southern hemisphere, therefore, it can not be seen from northern hemisphere. If the moon is above the horizon but close to it within the glare of the sun, then it may not be visible. The moon within the altitude of 10 degrees at sunset is usually not visible. Methods of Sighting the Crescent

51. Scientific Developments in Moon Sighting51 Main Factors for Crescent Visibility For a sightable crescent from any location, the following parameters are most important: Angular separation of the moon from sun as seen from earth. (this is called elongation, or arc of light, or simple angle from sun) Moon’s altitude above the horizon. Methods of Sighting the Crescent

52. Scientific Developments in Moon Sighting52 Main Factors for Crescent Visibility 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. A crescent seen by a person at any place will be seen by almost all the people in a group Methods of Sighting the Crescent

53. Scientific Developments in Moon Sighting53 Main Factors for Crescent Visibility 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. Methods of Sighting the Crescent

54. Scientific Developments in Moon Sighting54 Misconceptions about moon- sighting. Misconception 1: 29th day moon is always thin and 30th day moon is thick. Misconception 1: 29th day moon is always thin and 30th day moon is thick. Misconception 2: 29th day moon sets in a short time while 30th day moon remains longer on the horizon. Misconception 2: 29th day moon sets in a short time while 30th day moon remains longer on the horizon. Misconception 3: If the moon is thick and remains on the horizon a long time, it must be the 2nd day moon. Misconception 3: If the moon is thick and remains on the horizon a long time, it must be the 2nd day moon. Misconception 4: On New-moon day the dark side of the moon faces earth. Misconception 4: On New-moon day the dark side of the moon faces earth. Misconception 5: Three consecutive months of 30 days are not possible. Misconception 5: Three consecutive months of 30 days are not possible. Misconception 6: Full moon occurs on the 14th night. Misconception 6: Full moon occurs on the 14th night. Misconceptions on Moon-sighting

55. Scientific Developments in Moon Sighting55 Misconception 1: 29th day moon is always thin and 30th day moon is thick. It is very possible that the 30th day moon of one month is about the same thickness as 29th day moon of another month. This can be better explained by Figure 6.0 Misconceptions on Moon-sighting

56. Scientific Developments in Moon Sighting56 Misconception 1: 29th day moon is always thin and 30th day moon is thick. Misconceptions on Moon-sighting Moon closer to earthMoon farther from earth Earth Moon Earth Age = 20 hours Age = 25 hours Figure 6.0

57. Scientific Developments in Moon Sighting57 Misconception 1: 29th day moon is always thin and 30th day moon is thick. 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. In figure 6.0, the left hand side picture is an example of 29 th day moon of one month when it is closer to the earth and its age is 20 hours, while the right hand side of the picture shows 30 th day moon of another month that is farther from earth with the age 25 hours. To an observer from earth, both of these crescents would appear to be about the same thickness. Misconceptions on Moon-sighting

58. Scientific Developments in Moon Sighting58 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. This can be clarified with the help of Figure 7.0. Misconceptions on Moon-sighting

59. Scientific Developments in Moon Sighting59 Misconception 2: 29th day moon sets in a short time while 30th day moon remains longer on the horizon. Misconceptions on Moon-sighting Moon Horizon Sun 29th day at one location30th day at another location Figure 7.0

60. Scientific Developments in Moon Sighting60 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. This can clarified with the help of Figure 8.0 Misconceptions on Moon-sighting

61. Scientific Developments in Moon Sighting61 Misconception 3: If the moon is thick and remains on the horizon a long time, it must be the 2nd day moon. Misconceptions on Moon-sighting Sun Horizon Sun’s Glare Moon Figure 8.0

62. Scientific Developments in Moon Sighting62 Misconception 4: On New-moon day the dark side of the moon faces earth. 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. Misconceptions on Moon-sighting

63. Scientific Developments in Moon Sighting63 Misconception 5: Three consecutive months of 30 days are not possible. 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 a very wide area as one (Matla') horizon. Because of the elliptical orbit of the moon, two consecutive months of 30 days are quite common. Misconceptions on Moon-sighting

64. Scientific Developments in Moon Sighting64 Misconception 6: Full moon occurs on the 14th night. 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. Misconceptions on Moon-sighting

65. Scientific Developments in Moon Sighting65 Actual Saudi Dating System OLD SYSTEM before April 1999 OLD SYSTEM before April 1999 “It is adopted in Umm-ul-Qura Calendar that if the Moon's age at Sunset is 12 hours or more after the New Moon then the PREVIOUS day is the first day of the Islamic month, since the Islamic day starts at Sunset, and the night is before the daylight, as well as the time of fasting is in the civil daylight.” NEW SYSTEM as from April 1999 NEW SYSTEM as from April 1999 "To determine the beginnings of lunar months, the collaborators in the preparation of Umm Al-Qurrah calendar should adopt the SUNSET BEFORE THE MOONSET according to Mecca, and the coordinates of Al- Haram Mosque are adopted." Actual Saudi Dating System

66. Scientific Developments in Moon Sighting66 Actual Saudi Dating System It is gladding to note that the Saudis are now changing positively. However, the main issue still remains on the actual, physical sighting of the crescent. Check this site for the original documents http://www.jas.org.jo/sau.html Actual Saudi Dating System

67. Scientific Developments in Moon Sighting67 Expectations for this Ramadan in Abuja and Gusau Expectations for this Ramadan Earliest Moon Sighting Wednesday 8 th December, 1999 @ Lat 4°N Lon 90°W, Age 25.27hr. Gusau Abuja

68. Scientific Developments in Moon Sighting68 Lunar Eclipses 2000 - 2009 What’s Next?

69. Scientific Developments in Moon Sighting69 Lunar Eclipses 2000 - 2009 Muslims are advised to observe these eclipses in order to confirm to themselves that astronomical calculations are accurate. What’s Next?

70. Scientific Developments in Moon Sighting70 Solar Eclipses 2000 - 2009 What’s Next?

71. Scientific Developments in Moon Sighting71 Solar Eclipses 2000 - 2009 Note the highlighted dates. If we continue the attitude of commencing the month of Ramadan or celebrating Eid before the day of conjunction, then we are likely to commence fasting or celebrate Eid on a day of solar eclipse. That would be a clear proof that the crescent moon is yet to be sighted. What’s Next?

72. Scientific Developments in Moon Sighting72 When the above question was posed to an astronomer he replied: “Chaos, of course. As any self-respecting astronomer will tell you, the new millennium will not begin until January 1, 2001, but many people, if not most people will put logic aside and begin celebration on the evening of December 31, 1999. What’s Next? What is going to happen when the calendar changes to the year 2000

73. Scientific Developments in Moon Sighting73 What is going to happen when the calendar changes to the year 2000 Historians have looked over how humans have celebrated the beginning of a new century for the past two or three times and have found that we have always done the right thing in the past. It is a troubling example of how facts can sometimes be mandated by popular vote rather than by logic. I think an excellent exercise for students would be to review this issue and council their parents that they are doing the right thing a year too early”. Again note the highlighted words. Same applies to our attitudes towards sighting the crescent moon. What’s Next?

74. Scientific Developments in Moon Sighting74 What do we need to do? Develop a compendium for every town through collaboration of Muslim ulemas and astronomers. Use Newspapers to publish moon information Own our radio stations, TV stations and Newspapers Utilize/Optimize the use of Information Technology (IT) through Networking, Intranet, and Internet Pray to Allah to guide us and give us courage to change our attitudes toward acquiring knowledge as our first commandment is Read, i.e. seek knowledge. What’s Next?

75. Scientific Developments in Moon Sighting75 Conclusion In conclusion, I will now attempt to answer those questions posed at the beginning of the presentation:- Conclusion

76. Scientific Developments in Moon Sighting76 Conclusion 1. Yes, The morning hour moon seen in the east is decreasing moon that is seen on 27 th or 28 th of the Month that began with the actual moon sighting, not by conjunction date. Then the moon vanishes for about 24-30 hours and appears as a new crescent moon on western horizon in the evening of 29 th or 30 th. Conclusion Are there any relationships between crescent sighting at west in the evenings and moon sighting at east in the morning hours of the same day?

77. Scientific Developments in Moon Sighting77 Conclusion 2. No, there is nothing exceptional about our area to allow us consistently be the earliest observers of the crescent in the world. Conclusion Are we living in an area with peculiar geographic conditions that allow us to be among the earliest observers of the crescent in the world?

78. Scientific Developments in Moon Sighting78 Conclusion 3. Yes, solar eclipses occur at the instant of astronomical new moons. Conclusion Does moon sighting have relationship with eclipses?

79. Scientific Developments in Moon Sighting79 Conclusion Finally, concerning the first group that always sight the moon on the day of conjunction. It is impossible! Nobody could see the moon on the day of conjunction. However, I am not saying that somebody is lying. The second group that claims “the moon was seen at east in the morning and therefore could not have been sighted on the same day at west in the evening as a new crescent” is correct. Yes, the statement they make is correct. Conclusion

80. Scientific Developments in Moon Sighting80 References http://www.ummah.net/astronomy/index.html http://moonsighting.com/home.html http://www.iio.org/cfco/ http://www.columbia.edu/~mnd/ http://www.ummah.org.uk/ildl/mooncalc.html http://www.jas.org.jo/sau.html

81. Scientific Developments in Moon Sighting81 The End