Ibn Yunus (Arabic: ابن يونس) (full name, Abu al-Hasan 'Ali abi Sa'id 'Abd al-Rahman ibn Ahmad ibn Yunus al-Sadafi al-Misri) (c. 950-1009) was an important Egyptian mathematician and astronomer,^[1][2][3][4] whose works are noted for being ahead of their time, having been based on almost modern-like meticulous calculations and attention to detail. Arabic can mean: From or related to Arabia From or related to the Arabs The Arabic language; see also Arabic grammar The Arabic alphabet, used for expressing the languages of Arabic, Persian, Malay ( Jawi), Kurdish, Panjabi, Pashto, Sindhi and Urdu, among others. ... Events World Population: 250 Million. ... Events February 14: First known mention of Lithuania, in the annals of the monastery of Quedlinburg. ... Islamic mathematics is the profession of Muslim Mathematicians. ... This is a sub-article of Islamic science and astronomy. ...

The Ibn Yunus crater, on the Moon, is named after him. Ibn Yunas is the remains of a flooded lunar crater. ... This article is about Earths moon. ...

Life

Information regarding his early life and education is uncertain. He was born in Egypt between 950 and 952 AD and came from a respected family in Fustat. His father was a historian, biographer and scholar of hadith, who wrote two volumes about the history of Egypt—one about the Egyptians and one based on traveler commentary on Egypt.^[5] A prolific writer, Ibn Yunus' father has been described as "Egypt's most celebrated early historian and first known compiler of a biographical dictionary devoted exclusively to Egyptians".^[6] His great grandfather had been an associate of the noted legal scholar al-Shafi. Fostat (also spelled Fustat; Arabic: ) was the first capital city of Egypt under Arab rule. ... This article or section does not cite any references or sources. ...

Early in the life of Ibn Yunus, the Fatimid dynasty came to power and the new city of Cairo was founded. In Cairo, he worked as an astronomer for the Fatimid dynasty for twenty-six years, first for the Caliph al-Aziz and then for al-Hakim. Ibn Yunus dedicated his most famous astronomical work, al-Zij al-Hakimi al-kabir, to the latter. This handbook of astronomical tables contained very accurate observations, many of which may have been obtained with very large astronomical instruments. The Fatimids, Fatimid Caliphate or al-FātimiyyÅ«n (Arabic الفاطميون) is the Shia dynasty that ruled over varying areas of the Maghreb, Egypt, and the Levant from 5 January 910 to 1171. ... // For other uses, see Dynasty (disambiguation). ... Nickname: Egypt: Site of Cairo (top center) Coordinates: , Government  - Governor Dr. Abdul Azim Wazir Area  - City 214 km²  (82. ... For main article see: Caliphate The Caliph (pronounced khaleef in Arabic) is the head of state in a Caliphate, and the title for the leader of the Islamic Ummah, or global Islamic nation. ... Al-Aziz (* 955; † 996) was the fifth Caliph of the Fatimids (975-996). ... Al-Hakim is one of the names of Allah and may also refer to Al-Hakim bi-Amr Allah -- a Fatimid caliph Abdel-Aziz al-Hakim -- a Iraq, a President of Governing Council (2003) after the USA intervention in Iraq. ...

Works

Astrology

In astrology, noted for making predictions and having written the Kitab bulugh al-umniyya ("On the Attainment of Desire"), a work concerning the heliacal risings of Sirius, and on predictions concerning what day of the week the Coptic year will start on. Hand-coloured version of the anonymous Flammarion woodcut (1888). ... The heliacal rising of a star (or other body such as the moon or a planet) occurs when it first becomes visible above the eastern horizon at dawn, after a period where it was hidden below the horizon or when it was just above the horizon but hidden by the... Sirius B redirects here. ... The Coptic calendar, also called the Alexandrian calendar, is used by the Coptic Orthodox Church. ...

Astronomy

In astronomy, one remarkable aspect of his turn of the millennium calculations is that he took atmospheric refraction of the Sun's rays at the horizon into account in his observations. His figure of forty minutes of arc between the "true" horizon and the observed horizon is one of the oldest recorded values for this quantity. Two of the instruments said to have been used by him include an armillary sphere having nine rings, each of which was said to have weighed 2,000 pounds, and large enough for a horse and rider to pass through; and a copper astrolabe three cubits across. This is a sub-article of Islamic science and astronomy. ... Armillary sphere An armillary sphere (also known as spherical astrolabe) is a model of the celestial sphere, invented by Eratosthenes in 255 BC. Its name comes from the Latin armilla (circle, bracelet), since it has a skeleton made of graduated metal circles linking the poles and representing the equator, the... A 16th century astrolabe. ... Cubit is the name for any one of many units of measure used by various ancient peoples. ...

In the nineteenth century, Simon Newcomb found his observations reliable enough to use them in determining the secular acceleration of the moon. Simon Newcomb. ... This article is about Earths moon. ...

Mathematics

In mathematics, he demonstrated the trigonometric identity Islamic mathematics is the profession of Muslim Mathematicians. ... In mathematics, trigonometric identities are equations involving trigonometric functions that are true for all values of the occurring variables. ...

Poetry

Ibn Yunus is also thought to have been an Arabic poet, and to have used very large instruments in making his observations, though neither assertion is certain. Arabic poetry is poetry composed and written down in the Arabic language either by Arab people or non-Arabs. ...

Other works

He is said to have predicted his own death, seven days prior to the event, and without any outward sign of ill health.

Ibn Yunus is believed to have described an early type of pendulum in the 10th century. Some claimed that he used it for making measurements of time, but this is now believed to be a misinterpretation on the part of Edward Bernard, an English historian.^[7][8]

References

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 149th day of the year (150th in leap years) in the Gregorian calendar. ...

External links

• O'Connor, John J; Edmund F. Robertson "Abu'l-Hasan Ali ibn Abd al-Rahman ibn Yunus". MacTutor History of Mathematics archive.  
• Ibn Yunus Biography