28 Facts About Al-Battani

Al-Battani is considered to be the greatest and most famous of the astronomers of the medieval Islamic world.

Al-Battani's writings became instrumental in the development of science and astronomy in the west.

Al-Battani refined and corrected Ptolemy's Almagest, but included new ideas and astronomical tables of his own.

Al-Battani accurately calculated the Earth's obliquity, the solar year, and the equinoxes.

Al-Battani's tables were used by the German mathematician Christopher Clavius in reforming the Julian calendar, and the astronomers Tycho Brahe, Johannes Kepler, Galileo Galilei and Edmund Halley all used Al-Battani's observations.

Al-Battani introduced the use of sines and tangents in geometrical calculations, replacing the geometrical methods of the Greeks.

Al-Battani's equation was widely used until superseded by more accurate methods, introduced a century later by the polymath al-Biruni.

Al-Battani, whose full name was, and whose Latinized name was, was born before 858 in Harran, 44 kilometres southeast of the modern Turkish city of Urfa.

Al-Battani was the son of Jabir ibn Sinan al-Harrani, a maker of astronomical instruments.

Al-Battani's contemporary, the polymath Thabit ibn Qurra, was an adherent of Sabianism, which died out during the 11th century.

Al-Battani died in 929 at Qasr al-Jiss, near Samarra, after returning from Baghdad where he had resolved an unfair taxation grievance on behalf of a clan from Raqqa.

Al-Battani is considered to be the greatest and most famous of the known astronomers of the medieval Islamic world.

Al-Battani made more accurate observations of the night sky than any of his contemporaries, and was the first of a generation of new Islamic astronomers that followed the founding of the House of Wisdom in the 8th century.

Al-Battani's meticulously described methods allowed others to assess his results, but some of his explanations about the movements of the planets were poorly written, and have mistakes.

Al-Battani refined the observations found in Ptolemy's, and compiled new tables of the Sun and the Moon, previously long accepted as authoritative.

Al-Battani recommended that the astronomical instruments there were greater than one metre in size.

Al-Battani was one the first astronomers to observe that the distance between the Earth and the Sun varies during the year, which led him to understand the reason why annular solar eclipses occur.

Al-Battani observed changes in the direction of the Sun's apogee, as recorded by Ptolemy, and that as a result, the equation of time was subject to a slow cyclical variation.

Al-Battani's methods involved some of the most complex mathematics developed up to that time.

Al-Battani was aware of the superiority of trigonometry over geometrical chords, and demonstrated awareness of a relation between the sides and angles of a spherical triangle, now given by the expression:.

Al-Battani used the Iranian astronomer Habash al-Hasib al-Marwazi's idea of tangents to develop equations for calculating and compiling tables of both tangents and cotangents.

Al-Battani's equation was superseded a century after it was first used, when the polymath al-Biruni summarized several other methods to produce results that were more accurate than those that could be obtained using al-Battani's equation.

Al-Battani copied some data directly from Ptolemy's Handy Tables, but produced his own.

Al-Battani's work was published in three volumes, in 1899,1903, and 1907, by the Italian Orientalist Carlo Alfonso Nallino, who gave it the title.

Al-Battani's work was instrumental in the development of science and astronomy in the west.

Al-Battani influenced Jewish rabbis and philosophers such as Abraham ibn Ezra and Gersonides.

Al-Battani compared to his own value for the sidereal year with those obtained by al-Battani, Ptolemy and a value he attributed to the 9th-century scholar Thabit ibn Qurra.

Al-Battani's tables were used by the German mathematician Christopher Clavius in reforming the Julian calendar, leading to it being replaced by the Gregorian calendar in 1582.