The first day of Ramadan (and every other Islamic month) begins at sunset on the day that the new crescent moon is first seen trailing the sun at sunset. In 2010, the first day of Ramadan in Egypt was declared on the evening of the 10th August. If you searched for the crescent moon, however, you would have been disappointed.
If you go to the site of the Islamic Crescents’ Observation Project, you will discover that they have observers across the globe looking for the elusive crescent. From Indonesia through Norway, Libya, Senegal and the UK to the USA, not a single observer succeeded in identifying the crescent.
The reason is not hard to fathom, after all, astronomy has been charting and computing the heavens with increasing precision and understanding for over 5000 years.
The moon was in conjunction with the sun at 3.09 am (GMT) on the morning of 10th August. By sunset it had moved away from the sun by about 6 degrees. But this is still too close for it to be seen by the naked eye. The crescent would have been extremely fine and lost in the Sun’s glare. The following evening, the 11th August, the moon would have moved on a further 12 degrees when there would have been a much better chance to see it.
Saudi Arabia has decided to calculate the beginning of Ramadan from the moment of conjunction. So given that conjunction took place in the early morning of the 10th August, they were right to assume there would be a crescent moon that evening but wrong to think it would be visible.
Egypt has a similar algorithm to Saudi Arabia but only insists that Ramadan starts on the evening in which the young crescent moon sets at least 1 minute after the sun. Thus both Egypt and Saudi Arabia depend on astronomical calculations to set the beginning of Ramadan. Yet both go through the traditional ceremony of claiming a sighting. The Grand Mufti declared at 8.30 pm on the 10th August that Ramadan in Egypt would start that evening, based on local sightings, yet it’s not clear how those sightings were made. It would have been impossible to have seen the crescent moon with the naked eye or telescope.
The moon takes 29½ days to come back to the same position with respect to the sun. The next conjunction will therefore take place on the morning of 8th September at 10.30 am. By sunset, the moon will have moved on by only 4 degrees to form a fine crescent but will remain invisible to the naked eye or telescope. The following day it will have moved on a further 12 degrees, and though you will still be lucky to see it, the new month will start on this evening, the 9th August, and fasting will have ended for another year. This time the decision can be taken without having viewed the crescent moon for tradition and logic explain that if the lunar month is not 29 days then it must be 30 days whether the crescent moon is seen or not. But have a look yourself!
This blog first appeared as an article in the Cairo BCA Magazine for September, 2010, to encourage visitors to Sinai for star gazing with an 8″ Meade LX90 Telescope.