Thursday, October 11, 2007

Eid Mubarak!

Assalam wa alaikum warahmatullah wabarakutuh

Eid Mubarak to you all! The moon ws sighted in various places in the Muslim world on Thursday night (11th October), so Eid al-Fitr is on Friday 12th October 2007.




Anonymous said...

there are some people who say that scientifically it was impossible to "see" the moon on this day hence we must complete the 30 days,

if you have any knowledge with regards to these calculations it would be much appreciated. Are they definate? how accurate are these calculations? if it was not possibnle to visualise then obviously if anyone says they saw the moon they must have made a mistake etc?

Islamic Revival said...

The following is a summary of research into this subject compiled from both the works of Muslim and non-Muslim astronomers.

The Astronomical New Moon, or the invisible New Moon, is the moment when the moon is almost directly between the earth and the sun. At this moment the moon’s dark surface faces the earth. Therefore it is completely invisible even if it occurs in the middle of the night. The Astronomical New Moon occurs every 29 days, 12 hours, 44 minutes, and 2.8 seconds. The date and time of this invisible New Moon is commonly found in almanacs, newspapers and calendars.

The moon orbits around the earth in a predictable way and the earth orbits the sun in a predictable way. Therefore there are certain aspects of the moon (and sun) that can be calculated with a very high degree of accuracy. These aspects include:

1. The date/time of conjunction (astronomical new moon).

2. The altitude and azimuth of the moon and sun from any place on earth at a particular time.

3. The moonrise, moonset, sunrise and sunset times at a particular location.

4. The elongation of the moon.

5. The phase, age and width of the crescent.

The above information can be calculated. For example, conjunction time [birth of new moon] can be calculated to an accuracy of better than one second of time. Altitude and azimuth may be calculated to an accuracy of 1/100th of a degree or better.

Just knowing the above list of crescent information, which can always be calculated very accurately, can be useful in determining if a crescent is visible. For example:

 A new crescent (hilal) cannot be seen before conjunction [birth of the new moon] because it does not exist. Hence any claims of hilal sightings before conjunction must be wrong. For example if the moon is born on a day at 1.25am GMT (Grenwich Mean Time/ Universal Time) and someone claims to have seen the moon before this time, then they have definitely not sighted the new moon and have made a mistake. People sometimes may see some light in the sky or think they have sighted the new moon as it is very difficult to see.

 A new crescent cannot be seen after the moon has set because it is not above the horizon.

Issues that Astronomers disagree upon

The main issue of disagreement is about when the new crescent is visible – views on this subject have great disparity.

Ramadhan and Eid begin at sunset on the day of visual sighting of the lunar crescent. Even though visual sighting is necessary to determine the start of the month, it is useful to accurately predict when a crescent is likely to be visible in order to produce lunar calendars in advance. Although it is possible to calculate the position of the moon in the sky with high precision, it is often difficult to predict if a crescent will be visible from a particular location.

Visibility depends on a large number of factors including weather condition, the altitude of the moon at sunset, the closeness of the moon to the sun at sunset, the interval between sunset and moonset, atmospheric pollution, the quality of the eyesight of the observer, use of optical aids etc. Since ancient times, many civilisations and astronomers have tried to predict the likelihood of visualising the new moon using different ‘minimum visibility criteria’. However, all these criteria are subject to varying degrees of uncertainty and therefore the sighting of the moon by a Muslim should be accepted if the moon has been born, even if scientists differ over the possibility in terms of visibility of it. This is because the testimony of a Muslim is acceptable to us if it does not contradict something which is definite from reality. The issue of visibility is not a definite matter and is debated amongst the astronomers.

In summary, it would appear that the time of birth of the moon, as well as its movements, can be accurately predicted, although this is by no means precise. However the degree of precision is to within seconds with regard to the birth of the new moon.

In addition it would appear that the estimations and calculations as to where it will be possible to sight the moon are uncertain and are the subject of debate, discussion and differences amongst those with knowledge of this subject.

Abu Talha said...

Assalamualaikum Akhi!

We know that Luner month is either 29 or 30 days. My question is whether it is possible after 29 days that birth of moon did not take place? OR Is it definite that after 29 days birth of moon has already taken?

And given todays circumstances that many places have 2 days of difference in between them ( like Pakistan and saudia) then in one country its 29 days and in other its 27 days. Then is it possible that birth of moon takes place in both scenerios (after 27 days in Pakistan etc)?

I hope i made my question clear.