…or on the conjunction of the two heavenly bodies, their subsequent separation by a number of degrees, and the causes of the crescent’s first appearance, its becoming full, its disappearance, and of solar and lunar eclipses. That jurist therefore applied to the question of sighting the same ruling he had given on the lying, ignorant calculator. Next, those who, on the basis of computation, the configuration of the celestial spheres, and their motions, communicate information that is in fact correct are sometimes opposed by certain ignorant, ill-taught people—laymen who claim either to belong to the faith or to nothing at all. Such opponents imagine that the calculators have violated the religion by relying on arithmetic for crescent-sighting, or by following the alleged influences of the stars, whether beneficial or harmful. Seeing them engage in this practice—which is indeed forbidden in the Sacred Law—they proceed to reject everything the astronomers say in this field, without distinguishing between truths affirmed by revelation and reason and falsehoods that contradict both. Yet these critics are, in religious terms, in a better state than the first group: they deny part of the truth only out of mistaken interpretation and ignorance, without altering any of the fundamentals of Islam, whereas the first group may end up tampering with the very fabric of the religion. For we know with absolute certainty, as part of the religion of Islam, that in matters dependent upon the crescent—such as the beginning of the fast, the time for Ḥajj, waiting periods, oaths of abstention, and the like—it is impermissible to act on the statement of a calculator who claims that the moon will, or will not, be seen. Numerous, widely transmitted reports from the Prophet—may Allah bless him and grant him peace—attest to this, and the entire Muslim community has agreed upon it. No classical disagreement is known in this regard at all, nor any recent dissent—except that…