The critical edition and evaluation of Sharhu Sī Fasl by Nizām al-Dīn al-Nīsābūrī

Astronomy, the study of planets, stars, and celestial bodies, has long attracted the curiosity of humanity. From ancient times, people have constantly studied the sky and arranged their work accordingly by making certain calculations. So that as a result of the observations, they calculated the time, location, directions and many other things. In this way, they have made their lives simpler in many aspects from agriculture to trade, from prayer times to their daily lives. Astronomy has always played a significant role in human life and continues to do so now. Nīsābūrī's work called Sharhu Sī Fasl, which is the subject of our thesis, is one of the important works written in the field of astronomy. We aim to introduce this study to the scientific community by critical edition and evaluation. Nīsābūrī's work consists of thirty chapters. Each chapter contains basic information about astronomy, calendars and astrology. It should not be forgotten that particularly the critical editions created in the history of science, not only brings to light the scientific research carried out in ancient, but also makes it possible to utilize this information to conduct numerous comparisons and tests.