Abu Mahmood Khujandi or Abu Mahmud Hamid ibn al-Khidr Al-Khujandi (Persian: ابومحمود خجندی) was a Persian (Tajik) astronomer and mathematician who lived in the late 10th century and helped build an observatory near the city of Ray (near today's Tehran) in Iran . layout and formatting it should ensure no clashes with the top of the infobox Tajik ( - Tādjīk; UniPers: Tâjik; Cyrillic: Тоҷик is a term generally applied to Persian-speaking people of An observatory is a location used for observing terrestrial and/or celestial events See Rayshahr for the Sassanid center of learning in Fars province Tehran (or Teheran) ( Persian: تهران Tehrān) is the capital and largest City of Iran, and the administrative center of For a topic outline on this subject see List of basic Iran topics. He was born in Khudzhand (now Tajikistan) about 940 and died in 1000. Tajikistan (təˈdʒɪkɨstæn or /təˈdʒiːkɨstæn/ Тоҷикистон tɔʤikɪsˈtɔn or, Persian تاجیکستان taajikestaan officially the Republic of Events By Place Asia Saadia Gaon compiles his Siddur (Jewish prayer book in Iraq.
The few facts about Khujandi's life that are known come from both his surviving writings and comments made by Nassereddin Tusi. From Tusi's comments it is fairly certain that Khujandi was one of the rulers of the Mongol tribe in the Khudzhand region, and thus must have come from the nobility. Nobility is a government-privileged title which may be either hereditary (see Hereditary titles) or for a lifetime
In Islamic astronomy, Khujandi worked under the patronage of the Buwayhid Amirs of Ray, Iran, where he is known to have constructed the first huge mural sextant in 994 AD. The Buyids (آل بویه Āl-e Buye, Caspian: Bowyiyün also known as Buwaihids or Buyyids, were a Shī‘ah Iranian See Rayshahr for the Sassanid center of learning in Fars province This article is about the Sextant as used for Astrometry. For the navigator's sextant, see Sextant. 
Al-Khujandi accurately computed the axial tilt to be 23°32'19" (23. In Astronomy, axial tilt is the Inclination angle of a planet's rotational axis in relation to its orbital plane. 53°), which was a significant improvement over the Greek estimate of 23°51'20" (23. 86°) and still very close to the modern measurement of 23°26' (23. 44°).
In Islamic mathematics, he stated a special case of Fermat's last theorem for n = 3, but his attempted proof of the theorem was incorrect. Fermat's Last Theorem is the name of the statement in Number theory that It is impossible to separate any power higher than the second into two like The law of sines may have also been discovered by Khujandi, but it is uncertain whether he discovered it first, or whether Abu Nasr Mansur or Abul Wafa discovered it first. The law of sines ( sines law sine formula sine rule) in Trigonometry, is a statement about any Triangle in a plane Abu Nasr Mansur ibn Ali ibn Iraq (c 960 - 1036 was a was a Persian Muslim mathematician.