Al-Khazini

Abū al-Fath Abd al-Rahman Mansūr al-Khāzini or simply al-Khāzini (; flourished 1115–1130) was an Iranian astronomer, mechanician and physicist of Byzantine Greek origin who lived during the Seljuk Empire. His astronomical tables, written under the patronage of Sultan Sanjar ('''', 1115), are considered to be one of the major works in mathematical astronomy of the medieval period. He is considered to have been one of the greatest scientists of his era, among the greatest makers of scientific instruments of any time, and as "the physicist of all physicists".

Al-Khazini is one of the few Islamic astronomers to be known for doing original observations. He provided the positions of fixed stars, and for oblique ascensions and time-equations for the latitude of Marv in which he was based. He also wrote extensively on various calendrical systems and on the various manipulations of the calendars. He also devised the world's most precise instrument for weighing ordinary objects, determining specific gravities, and even examining the composition of alloys. On the basis of his detailed description, it has been possible to reconstruct his complex mechanism, which he dubbed "The Comprehensive Balance". Modern study affirms his claim to its extraordinary accuracy of 1:60,000.