(year of birth is unknown, died in 1430)

Mathematician and astronomer

 

 

He was born in the city of Qashqan (the city governed by Amir Temur, now under the authority of Iran). In 1413-14 he designed astronomical graphs dedicated to Shahruh , the son of Amir Temur (The governor of the state of Amir Temur at those times).

 

He moved to Samarkand in 1417, after the madrasah of Ulughbek had been constructed, and started to work with Ali Qushchi and Qazi-zade Rumi under the guidance of Ulughbek.  He was actively involved in designing and construction of the famous observatory of Ulughbek, but unfortunately died before the end of the construction works. He was buried in Samarkand.

 

 

Following is the list of his manuscripts written in the Persian language:

 

Miftah al-hisab («The Key to Arithmetic») – the main work by al-Qashi, providing comprehensive description of all knowledge in arithmetic and algebra. This is highly valued by the historians of the science, and translated into most European languages;

 

Ar-Risala al-muhitiyya («The Treatise on Circumference») – a manuscript dedicated to calculation of the number of π (p) and sin 1° with a precision which was deemed very high for that period of time;

 

Zidj Haqani dar taqmili zidji Elhani («Zij Haqana») – astronomic graphs devoted to Shahruh.

 

 His letter to his father, in which he had provided valuable information on the academy of Ulughbek, was translated into many European and Asian languages.

 

 

The main contribution to the world science made by Mirza Ulughbek was the catalogue of 1018. Gipparh – the Greek astronomer made first compilation of the star catalogue in the II century B.C. Later, astronomers would make changes to the catalogue compiled by Gipparh, however making no original observations. As, at the beginning of the XV century the deviations between the real location of stars in the sky and their coordinates had become considerably apparent, Mirza Ulughbek decided to make his own investigation of the coordinates of stars. So the chart designed by him became the first after Gipparh’ catalogue (i.e. over 16 centuries!) based on the original astronomic measurements and calculations. This became a true everlasting scientific value of “Zij” described by Ulughbek.

 

 

The main text of his major manuscript “New Guragan Astronomic Charts” starts with trigonometric charts of extremely high precision. The sine table is designed with 1 minute pace, the tangent table with the gap of 1–45 degrees at 1 minute pace, however the tables made with the interval of 45–90 degrees – at a pace of 5 minutes. The values up to the fifth within the 60-th numeration system, which provides from 7 to 12 precise values converted into decimal system of numeration, i.e. the table were made with a precision of 10–7–10–12.

 

Aiming at finding the value of sin1° of high precision Ulughbek and his associates developed a method of consecutive approximations, which is described in his treatise «Calculation of the Sine of One Degree».

 

In view of designing his trigonometric charts which required calculating trigonometric functions and coordinates of stars at high precision in big quantities, Ulughbek had opened a research center which later turned into a prototype of contemporary computing centres.

 

 

Mirza Ulughbek will forever be remembered as a man wholly devoted himself to the science. In the mid of XVII century, the outstanding Polish astronomer Yan Geveliy completed his manuscript “Beginning of astronomy” with the catalogue developed by Ulughbek. He furnished his manuscript with two engravings in which Ulughbek is depicted in a group with famous astronomers lived in all times. These engravings are encountered in textbooks of astronomy and treatises on the history of this science. They are now considered as precious treasure faming the astronomer school of Ulughbek. Name of Ulughbek has been immortalized in the name of one of the craters on the Moon (XVII century). One of the minor planets of the solar system discovered in 1977 and registered in the Harvard Center under Ref. № 2439 was given his name.