may Allah bless him and grant him peace, that he said:

“Whatever lies between east and west is qiblah.”

Al-Tirmidhī said: “An authentic hadith.” Thus, according to the great majority of scholars, a person praying need not determine the direction by the celestial pole, the Pole Star, or anything else. Rather, if someone in Syria or a similar region places west to his right and east to his left, his prayer is valid.

Likewise, the time when the new crescent appears cannot be precisely determined by calculation. Although they know that the moon derives its light from the sun, that no light from it is visible when the two discs come into conjunction during the moon’s dark phase, and that light appears on it as it moves away from the sun, the most they can determine by calculation is its distance from the sun at sunset. This assumes that their calculation of celestial positions and their corrections are accurate. They call this the science of calculating and correcting celestial positions because they take the highest and lowest values of the celestial bodies’ motion, determine their mean, and calculate on that basis.

Even supposing that they have estimated its altitude at sunset, this provides no indication that it will or will not be visible. Visibility is a matter of sensory perception affected by numerous factors: the clarity or haziness of the air, the observer’s higher or lower vantage point, and the sharpness or weakness of eyesight. One person may not see it, while another with sharper eyesight does, and so forth.

For this reason, the early scholars of astronomy, such as Ptolemy, the author of the Almagest, and others, did not say a single word about this. Only some later scholars, such as Kūshyār al-Daylamī and others like him, addressed it. When they saw that the revealed Law made sighting the criterion, they wished to determine it by calculation