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Abu-Mahmud Khojandi
Abu Mahmud Hamid ibn al-Khidr al-Khujandi (known as Abu Mahmood Khujandi, al-khujandi or Khujandi, Persian: ابومحمود خجندی, – 1000) was a Transoxanian astronomer and mathematician born in Khujand (now part of Tajikistan) who lived in the late 10th century and helped build an observatory, near the city of Ray (near today's Tehran), in Iran. Astronomy Khujandi worked under the patronage of the Buwayhid Amirs at the observatory near Ray, Iran, where he is known to have constructed the first huge mural sextant in 994 AD, intended to determine the Earth's axial tilt ("obliquity of the ecliptic") to high precision. He determined the axial tilt to be 23°32'19" for the year 994 AD. He noted that measurements by earlier astronomers had found higher values (Indians: 24°; Ptolemy 23° 51') and thus discovered that the axial tilt is not constant but is in fact (currently) decreasing. His measurement of the axial tilt was however about 2 minutes too small, probably due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Khujand
Khujand, sometimes spelled Khodjent and formerly known as Leninabad from 1936 to 1991, is the second-largest city of Tajikistan and the capital of Tajikistan's northernmost Sughd province. Khujand is one of the oldest cities in Central Asia, dating back about 2,500 years to the Persian Empire. Situated on the Syr Darya river at the mouth of the Fergana Valley, Khujand was a major city along the ancient Silk Road. After being captured by Alexander the Great in 329 BC, it was renamed Alexandria Eschate and has since been part of various empires in history, including the Umayyad Caliphate (8th century), the Mongol Empire (13th century) and the Russian empire (19th century). Today, the majority of its population are ethnic Tajiks and the city is close to the present borders of both Uzbekistan and Kyrgyzstan. History Antiquity Khujand may have been the site of Cyropolis () which was established when King Cyrus the Great founded the city during his last expedition against the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextant (astronomical)
In astronomy, sextants are devices depicting a sixth of a circle, used primarily for measuring the position of stars. There are two types of astronomical sextants, mural instruments and frame-based instruments. They are of significant historical importance, but have been replaced over time by transit telescopes, other astrometry techniques, and satellites such as Hipparcos. Mural sextants The first known mural sextant was constructed in Ray, Iran, by Abu-Mahmud al-Khujandi in 994. To measure the obliquity of the ecliptic, al-Khujandī invented a device that he called ''al-Fakhri sextant'' (al-suds al Fakhrī), a reference to his patron, Buwayhid ruler, Fakhr al Dawla (976–997). This instrument was a sixty-degree arc on a wall aligned along a meridian (north–south) line. Al Khujandi's instrument was larger than previous instruments; it had a radius of about twenty meters. Tekeli, Sevim (1958), 'Nasiruddin, Takiyuddin ve Tycho Brahe'nin Rasat Aletlerinin mukayesesi'. ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inventors Of The Medieval Islamic World
An invention is a unique or novel device, method, composition, idea, or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an idea is unique enough either as a stand-alone invention or as a significant improvement over the work of others, it can be patented. A patent, if granted, gives the inventor a proprietary interest in the patent over a specific period of time, which can be licensed for financial gain. An inventor creates or discovers an invention. The word ''inventor'' comes from the Latin verb ''invenire'', ''invent-'', to find. Although inventing is closely associated with science and engineering, inventors are not necessarily engineers or scientists. The ideation process may be augmented by the applications of algorithms and methods from the domain collectively known as artificial intelligence . Some inventions can be patented. The system of patents was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomers Of The Medieval Islamic World
An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers typically fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate Con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
10th-century Iranian Astronomers
1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sports, where it commonly denotes the first, leading, or top thing in a group. 1 is the unit of counting or measurement, a determiner for singular nouns, and a gender-neutral pronoun. Historically, the representation of 1 evolved from ancient Sumerian and Babylonian symbols to the modern Arabic numeral. In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 1 is by convention not considered a prime number. In digital technology, 1 represents the "on" state in binary code, the foundation of computing. Philosophically, 1 symbolizes the ultimate reality or source of existence in various traditions. In mathematics The number 1 is the first natural number after 0. Each natural numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1000 Deaths
In the proleptic Gregorian calendar, it was a non-leap century year starting on Wednesday (like 1800). The year falls well into the period of Old World history known as the Middle Ages; in Europe, it is sometimes and by convention considered the boundary date between the Early Middle Ages and the High Middle Ages. The Muslim world was in its Islamic Golden Age. China was in its Song dynasty, Korea was in its Goryeo dynasty, Japan was in its classical Heian period. India was divided into a number of lesser empires, such as the Eastern Chalukyas, Pala Empire ( Kamboja Pala dynasty; Mahipala), Chola dynasty ( Rajaraja I), Yadava dynasty, etc. Sub-Saharan Africa was still in the prehistoric period, although Trans-Saharan slave trade was beginning to be an important factor in the formation of the Sahelian kingdoms. The pre-Columbian New World was in a time of general transition in many regions. Wari and Tiwanaku cultures receded in power and influence while Chachapoya and Chi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
940s Births
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94 may refer to: * 94 (number) * one of the years 94 BC, AD 94, 1994, 2094, etc. * Atomic number 94: plutonium * Saab 94, a roadster * 94 Aurora, a main-belt asteroid See also * * List of highways numbered All lists of highways beginning with a number. {{List of highways numbered index Lists of transport lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictionary Of Scientific Biography
The ''Dictionary of Scientific Biography'' is a scholarly reference work that was published from 1970 through 1980 by publisher Charles Scribner's Sons, with main editor the science historian Charles Coulston Gillispie, Charles Gillispie, from Princeton University. It consisted of sixteen volumes. It is supplemented by the ''New Dictionary of Scientific Biography'' (2007). Both these publications are included in a later ebook, electronic book, called the ''Complete Dictionary of Scientific Biography''. ''Dictionary of Scientific Biography'' The ''Dictionary of Scientific Biography'' is a scholarly English-language reference work consisting of biography, biographies of scientists from antiquity to modern times but excluding scientists who were alive when the ''Dictionary'' was first published. It includes scientists who worked in the areas of mathematics, physics, chemistry, biology, and earth sciences. The work is notable for being one of the most substantial reference works in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasir Al-Din Al-Tusi
Muḥammad ibn Muḥammad ibn al-Ḥasan al-Ṭūsī (1201 – 1274), also known as Naṣīr al-Dīn al-Ṭūsī (; ) or simply as (al-)Tusi, was a Persians, Persian polymath, architect, Early Islamic philosophy, philosopher, Islamic medicine, physician, Islamic science, scientist, and kalam, theologian. Nasir al-Din al-Tusi was a well published author, writing on subjects of math, engineering, prose, and mysticism. Additionally, al-Tusi made several scientific advancements. In astronomy, al-Tusi created very accurate tables of planetary motion, an updated planetary model, and critiques of Ptolemaic astronomy. He also made strides in logic, mathematics but especially trigonometry, biology, and chemistry. Nasir al-Din al-Tusi left behind a great legacy as well. Tusi is widely regarded as one of the greatest scientists of medieval Islam, since he is often considered the creator of trigonometry as a mathematical discipline in its own right. The Muslim scholar Ibn Khaldun (1332–1406) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abū Al-Wafā' Al-Būzjānī
Abū al-Wafāʾ Muḥammad ibn Muḥammad ibn Yaḥyā ibn Ismāʿīl ibn al-ʿAbbās al-Būzjānī or Abū al-Wafā Būzhjānī (, ; 10 June 940 – 15 July 998) was a Persian mathematician and astronomer who worked in Baghdad. He made important innovations in spherical trigonometry, and his work on arithmetic for businessmen contains the first instance of using negative numbers in a medieval Islamic text. He is also credited with compiling the tables of sines and tangents at 15 ' intervals. He also introduced the secant and cosecant functions, as well studied the interrelations between the six trigonometric lines associated with an arc. His ''Almagest'' was widely read by medieval Arabic astronomers in the centuries after his death. He is known to have written several other books that have not survived. Life He was born in Buzhgan, (now Torbat-e Jam) in Khorasan (in today's Iran). At age 19, in 959, he moved to Baghdad and remained there until his death in 998. He was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abu Nasr Mansur
Abū Naṣr Manṣūr ibn ʿAlī ibn ʿIrāq al-Jaʿdī (; c. 960 – 1036) was a Persian Muslim mathematician and astronomer. He is well known for his work with the spherical sine law.Bijli suggests that three mathematicians are in contention for the honor, Alkhujandi, Abdul-Wafa and Mansur, leaving out Nasiruddin Tusi. Bijli, Shah Muhammad and Delli, Idarah-i Adabiyāt-i (2004) ''Early Muslims and their contribution to science: ninth to fourteenth century'' Idarah-i Adabiyat-i Delli, Delhi, India, page 44, Abu Nasri Mansur was born in Gilan, Persia, to the ruling family of Khwarezm, the Afrighids. He was thus a prince within the political sphere. He was a student of Abu'l-Wafa and a teacher of and also an important colleague of the mathematician, Al-Biruni. Together, they were responsible for great discoveries in mathematics and dedicated many works to one another. Most of Abu Nasri's work focused on mathematics, but some of his writings were on astronomy. In mathemati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Law Of Sines
In trigonometry, the law of sines (sometimes called the sine formula or sine rule) is a mathematical equation relating the lengths of the sides of any triangle to the sines of its angles. According to the law, \frac \,=\, \frac \,=\, \frac \,=\, 2R, where , and are the lengths of the sides of a triangle, and , and are the opposite angles (see figure 2), while is the radius of the triangle's circumcircle. When the last part of the equation is not used, the law is sometimes stated using the Multiplicative inverse, reciprocals; \frac \,=\, \frac \,=\, \frac. The law of sines can be used to compute the remaining sides of a triangle when two angles and a side are known—a technique known as triangulation. It can also be used when two sides and one of the non-enclosed angles are known. In some such cases, the triangle is not uniquely determined by this data (called the ''ambiguous case'') and the technique gives two possible values for the enclosed angle. The law of sines is on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
