Moon Sighting: Scientific Perspective

29:38

1 May 2015

Astronomy

Salman Hameed

Akif Khan

Akif Khan and Salman Hameed discuss the topic of moon sighting, the method through which the start of months of the Islamic calendar are identified.  Khan jokes that it could also be called “moon fighting”, as announcements about the sighting of the moon (or not) can make the beginning of holidays rather chaotic.

They start by discussing how Hameed became interested in astronomy, watching Carl Sagan on Cosmos, realizing that professional astronomy was a possibility.

Hameed describes the Moon’s phases from an astronomer’s perspective.  He notes how the well-documented orbit of the Moon around the Earth means that the calculations for the phases are very precise and can readily be known far into the future.  He clarifies how the structure of the religious sighting of the Moon differs:  because it needs to be sighted with the human eye, and because of variations in atmospheric conditions (cloud, haze, etc), it is unclear how far past the astronomical new moon an observer must be before the new crescent is visible.  Hameed suggests that at approximately 14 hours past the astronomical new moon, the crescent becomes possible to be viewed with the naked eye on Earth under optimal viewing conditions.  For less optimal conditions, perhaps 18 or 20 hours past the astronomical new moon.

The pair discuss the problems experienced in Pakistan about sighting the Moon, including attempting to sight the new crescent from less than optimal locations.  They suggest that standardizing the calendar based on some mark would eliminate all the problems, and allow people to plan ahead.  Hameed mentions various ways this standardization could occur, from using the astronomical new moon to choosing a standard offset from the astronomical new moon, to centering the viewing based on what is seen (based on astronomical measurement) in Mecca.

Hameed notes that it is likely only a matter of time before this standardization will be forced to occur.  He suggests that people will be living on the Moon itself or on Mars within the next century or two, and will thus be unable to sight the Moon’s crescent with the naked eye from those locations.  At that point, some standard will have to be used.

The video is part of a media documentary series by the Rationalist Society of Pakistan.  This video was directed by Akif Khan, and the media coordinator was Anila Athar.

Evaluation:

Islam:  The material on Islam is within the bounds of what Muslims have historically understood as acceptable.

Science:  The scientific discussion here is accepted by contemporary scientists.

History:  There is insufficient historical material on which to base an evaluation.