Validation of the Definitive Calculations of the Birth of the Moon in the Legal Proving of the Crescent

In the challenging issue of proving the emergence of the crescent of the lunar month, most jurists, based on the appearance of evidence, consider the sensory vision as the only criterion. However, with the new scientific findings, the exact time of the birth of the moon can be determined with certainty. This article tries to challenge the popular opinion and the sufficiency of sensory vision by analytical method using library sources to prove the validity of the definitive calculations of the birth of the moon and its compatibility with verses and hadiths. According to the results of the article, the Legislator (Shāriʿ) has not provided a new definition of the time frame of the obligation (Shahr) and has introduced the vision as the most conventional way of certainty to prove the crescent. In addition, the rejection of alternative ways other than vision, have been due to the invalidity of suspicion and estimation. The article, after presenting the introductory topics, reconsiders the evidence and evaluates the most important drawbacks of the lunar birth theory.