Najm al‐Dīn al‐Miṣrī ( ar, نجم الدين المصري) was a 14th-century Egyptian

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

mostly known for writing a large astronomical table that had nearly 415,000 entries. The table is considered to be the largest of its kind ever produced by one person during the

Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...

. Although the main purpose of the work was astronomical timekeeping, it can also be used to solve all problems of

spherical trigonometry Spherical trigonometry is the branch of spherical geometry that deals with the metrical relationships between the sides and angles of spherical triangles, traditionally expressed using trigonometric functions. On the sphere, geodesics are grea ...

by changing the arguments of the table. Najm al‐Din also wrote an important illustrated treatise that describes more than 100 different astronomical instruments, such as

astrolabes An astrolabe ( grc, ἀστρολάβος ; ar, ٱلأَسْطُرلاب ; persian, ستاره‌یاب ) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclin ...

quadrants Quadrant may refer to: Companies * Quadrant Cycle Company, 1899 manufacturers in Britain of the Quadrant motorcar * Quadrant (motorcycles), one of the earliest British motorcycle manufacturers, established in Birmingham in 1901 * Quadrant Privat ...

and

sundials A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat ...

, including ones he invented himself. This work is of high importance for modern scholars and one of the main sources on the subject.

References

{{DEFAULTSORT:Najm al-Din al-Misri 14th-century astronomers Medieval Egyptian astronomers Scientists from Cairo