in category Fiqh (Jurisprudence)

How important are the charts used to determine moon sighting for Ramadan?

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One of the biggest diseases when it comes to splits over sighting the new moon is these sighting charts.

They are fundamentally scientifically flawed for the following reasons:

  • They use an outdated and scientifically discredited idea of the danjon limit. It's now believed no such limit exists.
  • It Is a probabilistic chart meaning it is dhanni (indefinite) and not certain. To use this chart to discount the actual testimony of a person has no basis whatsoever.
  • These charts are built on assumptions that are not scientifically proven but subjective. E.g. They do not account for testimonies of sighting before sunset, or they only refer to non Muslim amateur scientists for "verified sightings" thus ignoring many testimonies from Muslims themselves.

This is what moonsighting.com claim note they use a criteria that is based on cities, with light pollution and after sunset...

"Please note that our visibility maps are calculated for visibility at local sunset time at every point on the globe for a specific date. All those calculations are based on the collected observation data after sunset (from 1860 AD to the present) from different locations on the globe. The data of observations we have were all from cities which have city lights, city pollution and after sunset. We do not have any data for sighting before sunset. New evidence show that Saudi claims of sighting comes from desert areas and many times the sightings were before sunset. We, at moonsighting.comstarted calculating the possibility of sighting before sunset and our finding for sighting possibility before sunset (under consideraion of Saudi desert areas) was a big surprise. The moon being few degrees above the horizon before sunset may have been seen, which would set in a short time and would not be visible if people try to see it after sunset. It should also be noted that the new crescent moon in desert areas with dry climate and no city lights and no city pollution would have very different refraction effects. "

Therefore to use a probabilistic indefinite sighting chart to discount a valid testimony is wrong and needs a fundamental reconsideration from those that use it.

Most if not all Muslims who attempt to use it do not even understand the "science" nor its probabilistic nature behind these charts, yet take it as though it is certain (qati).

Finally there are no possible calculations to determine sighting with certainty due to a large number of variables that cannot be predicted for:

1. Light pollution

2. Luminosity at twilight

3. Wind direction

4. Humidity

5. Atmospheric pressure

6. The level of eyesight of the individual(s) viewing the moon.

That's in addition to the elliptical orbit of the moon (gets closer towards the earth at certain periods), resulting in a variable speed of the moon.

All this makes it impossible to use calculations to determine when it is possible to sight the moon. It is unacceptable to use dhanni calculations whilst disregarding the divine texts commands to follow valid testimony - even if there's still a possibility of error we are still commanded explicitly to follow this.

Thus these charts should be abandoned.

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