Modern astronomy calculations for the sighting of the crescent

Question:

In some countries, the day and date of ‛id is delineated a few days
before the end of Ramadan, and an announcement to this effect is
made. Those who do this claim that it is possible through modern
astronomy calculations. What is the ruling of the Shari‛ah with regard
to such calculations?

Answer:

The opinions of astronomers and astrophysicists is not worthy of
consideration as regards sighting of the crescent. Therefore, the
sighting of the crescent based on their calculations will not be established. The Shari‛ah has linked fasting and ‛id to the sighting of
the crescent. Therefore, the opinions of astronomers – no matter how
intricate calculations they may be based on – are never totally
absolute. In fact, in most cases, their opinions differ with each other.
Yes, modern astronomy can be used for the negative, but there is no
room for using it for the positive. However, that which is absolutely
certain can be accepted as a supporting evidence.

Imam AbB Han3fah rahimahullah, Imam Malik rahimahullah, Imam
Ahmad rahimahullah and the jurists in general concur that it is not
permissible to decide on Ramadn and ‛3d on the basis of astronomy
and its calculations.

For more details refer to: Fatawa Faridiyyah, vol. 4, p. 40; Fatawa Dar al-
‛Ul’m Deoband, vol. 6, p. 367.

Allah ta‛ala knows best.