Nigeria is sighting the wrong moon (2)
This is a continuation of Engr. A. A. Aziz’s presentation titled Scientific Developments in Moon Sighting
Locating 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.
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.
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 Sun.
Factors determining crescent visibility
Other factors responsible for crescent visibility are: 1) the angular distance between the centers of Sun and Moon 2) The crescent's altitude 3) The Moon's staying (the interval between the Sunset and the Moon 4) The azimuth difference between the Sun and the Moon.
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.
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.
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:
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).
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. In order to obtain an idea as to approximately where to look, the following information on LUNAL ORBIT is useful:
. 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.
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.
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.
Criteria for crescent 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.
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 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.
3. Some countries adopt specific criteria, such as the Moon's age, altitude, the interval between Sunset and Moonset, etc., and if the Moon fulfills these criteria at Sunset, then the following day is the first day of the Islamic Month.
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!
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
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.
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.
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.
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 sunlight. 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 cannot 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.
Another important factor is the moon's altitude above horizon. If the crescent thickness is sufficient, but it is not above horizon, then it cannot be seen. This happens in the month of September and October in northern hemisphere, when the moon is in the southern hemisphere, therefore, it cannot 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.
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.
Misconceptions about moon sighting
Common misconceptions about moon sighting are: 1) 29th day moon is always thin and 30th day moon is thick. 2) 29th day moon sets in a short time while 30th day moon remains longer on the horizon. 3 If the moon is thick and remains on the horizon a long time, it must be the 2nd day moon. 4) On New-moon day the dark side of the moon faces earth. 5) Three consecutive months of 30 days are not possible.6) Full moon occurs on the 14th night.
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.
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 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.
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.
What do we need to do?
We need to 1) develop a compendium for every town through collaboration of Ulema and astronomers. 2) Use newspapers to publish moon information. 3) Own our radio stations, TV stations and newspapers. 4) Utilize/optimize the use of Information Technology through Networking, Intranet and Internet. 5) 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.
In conclusion, I will now attempt to answer those questions posed at the beginning of the presentation:
1. Yes, the morning hour moon seen in the east is decreasing moon that is 27th or 28th 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 29th or 30th.
2. No, there is nothing exceptional about our area to allow us consistently be the earliest observers of the crescent in the world.
3. Yes, solar eclipse occurs at the instant of astronomical new moons.
4. Finally, concerning the first group that always sights 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.
5. 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. THE END.
Comment: Engr. Aziz has appended a table of Solar and Lunar Ephemeris for Abuja. According to the calculations, the astronomical new moon of Ramadan this year will start at 12:13 AM on Saturday, November 26th. It is impossible to see the moon before then. But later, at sunset of the following evening, the new moon will be 17:53 hrs old. It will then be possible to sight it as a crescent. We can therefore look forward to start fasting the following morning, Sunday, Nov. 26, 2000., in sha Allah.
May God guide us to the Right Path. Amen.