مبحث تقويم در زيج جامع كوشيار گيلاني (براساس ترجمه فارسي كهني از قرن پنجم)

An Early Persian Translation of the Section on Calenedars in Kushyarʹs Zij

The first section of Book I of al-Zij al-Jami (The Comprehensive astronomical tables) by Kushyar ibn Labban al-Jili (Gilani), the Iranian astronomer who lived around ten centuries ago, is dedicated to the subject of calendars. In this section, Kushyar describes different types of calendars known in his time, their characteristics, and the methods for converting them into each other. Edition of an early Persian translation of this section, with introduction and commentary is provided in this article.