Moon's radio glow could keep Muslim calendars in sync

Is it Ramadan yet? Muslim communities look for the new moon to decide, and radio waves could settle the matter.

The Islamic calendar is based on lunar months, with sightings of the first sliver of the waxing moon marking the start of each month. It is possible to calculate when this thin crescent will theoretically be visible, but many Muslims will only accept visual confirmation.

Religious authorities in each country conduct their own lunar observations, so cloudy skies can delay the start of a new month by a day or two in some countries relative to others. This means that Muslims around the world can get slightly out of sync when marking festivals and the start and end of the holy month of Ramadan.

Radio resolution

Radio observations could bring calendars more into line, says a team led by Yaser Hafez at the King Abdulaziz City for Science and Technology, the Saudi Arabian science agency in Riyadh. Solar radiation bouncing off the moon creates a distinct glow for radio astronomers, even in cloudy conditions. Using a 3.7-metre radio telescope - essentially a scaled-up version of a satellite TV dish - the team could lock on to the new moon's radio signal at the same time that the first thin crescent appeared in visible light.

Traditionalists will probably prefer visual confirmation, says Khalid Shaukat, who runs the Islamic astronomy website But the team argues that its method might help resolve matters in the event of a disputed sighting by demonstrating that the disc of the moon has indeed moved past the sun as seen from Earth, an alignment that means the new moon should be visible. "It is something to show the people: the real locations and the images of the actual two objects," says Hafez.

"All this telescope does is locate the moon's position, so it is complementary to the visual way of doing it," agrees team member Clive Dickinson at the University of Manchester, UK.


Journal reference: Monthly Notices of the Royal Astronomical Society, DOI: 10.1093/mnras/stt2476


Source: New Scientist

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  2 Comments   Comment

  1. Dr. Salman Shaikh from United States


    Radio telescopes will show a round moon, not crescent shaped Hilal

    and may result in changing the date from what would result in naked-

    eye sighting of Hilal and hence are not acceptable.

    The root problem for world wide confusion is due to frequent errors

    in Saudi Arabia, usually from two individuals - one in Sharqah and

    one in Hauta Sudayr while all the 9 official Saudi moonsighting

    committees report negative sighting. Several hours after the Saudi

    announcements, when the sun sets in countries west of Saudi -

    Morocco and USA, they often can't see the hilal in spite of clear

    skies, even though in this extra time it should become bigger,

    higher and stay longer. This is a proof of Saudi errors. Just check

    the results in Morocco and South Africa.

    The problem can be solved inshaAllaah by requiring Jamme Ghafeer -

    or large number of witnesses, especially when the Astronomical

    models like the ones at indicate no possibility of sighting as

    mentioned by Fatwa of Mufti Taqi Usmani and others. For more details

    please see website.

    May Allaah SWT guide to the best. Aameen.

    Salman Shaikh, Ph.D.

    Coordinator, Hilal Sighting Committee of North America

  2. Babandi A.Gumel from U.K

    Masha Allah ikhtilaf is Rahamah for the Ummah.Some brothers and

    sisters may accept the new Scientific concept as time changes while

    others will like to cling to the traditional method with no addition

    .All of them may be right and may argue all following Sunnah the

    traditional and new ijtihad which is blessing.This is the reason why

    I said from the beginning Itktilaf is Rahamah for the Ummah matter

    of choice.