Astronomy in the medieval Islamic worldMedieval Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries), and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa, and later in the Far East and India. It closely parallels the genesis of other Islamic sciences in its assimilation of foreign material and the amalgamation of the disparate elements of that material to create a science with Islamic characteristics.
Pole starA pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body. Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude 2 star aligned approximately with its northern axis that serves as a pre-eminent star in celestial navigation, and a much dimmer magnitude 5.5 star on its southern axis, Polaris Australis (Sigma Octantis). From around 1700 BC until just after 300 AD, Kochab (Beta Ursae Minoris) and Pherkad (Gamma Ursae Minoris) were twin northern pole stars, though neither was as close to the pole as Polaris is now.
Chongzhen EmperorThe Chongzhen Emperor (; 6 February 1611 – 25 April 1644), personal name Zhu Youjian (), courtesy name Deyue (德約), was the 17th and last Emperor of the Ming dynasty. He reigned from 1627 to 1644. "Chongzhen", the era name of his reign, means "honorable and auspicious." Zhu Youjian was son of the Taichang Emperor and younger brother of the Tianqi Emperor, whom he succeeded to the throne in 1627. He battled peasant rebellions and was not able to defend the northern frontier against the Manchu.
Shunzhi EmperorThe Shunzhi Emperor (Fulin; 15 March 1638 – 5 February 1661) was the second emperor of the Qing dynasty of China, and the first Qing emperor to rule over China proper, reigning from 1644 to 1661. A committee of Manchu princes chose him to succeed his father, Hong Taiji (1592–1643), in September 1643, when he was five years old. The princes also appointed two co-regents: Dorgon (1612–1650), the 14th son of the Qing dynasty's founder Nurhaci (1559–1626), and Jirgalang (1599–1655), one of Nurhaci's nephews, both of whom were members of the Qing imperial clan.
Emperor Xuanzong of TangEmperor Xuanzong of Tang (xuan3.zong1; 8 September 685 – 3 May 762), personal name Li Longji, was the seventh emperor of the Tang dynasty in China, reigning from 712 to 756 CE. His reign of 44 years was the longest during the Tang dynasty. Through two palace coups, he seized the throne and inherited an empire still in its golden age. He was initially assisted by capable chancellors like Yao Chong, Song Jing and Zhang Yue who were already serving as government officials before Xuanzong ascended the throne.
AlmanacAn almanac (also spelled almanack and almanach) is a regularly published listing of a set of current information about one or multiple subjects. It includes information like weather forecasts, farmers' planting dates, tide tables, and other tabular data often arranged according to the calendar. Celestial figures and various statistics are found in almanacs, such as the rising and setting times of the Sun and Moon, dates of eclipses, hours of high and low tides, and religious festivals.
Fixed starsIn astronomy, the fixed stars (stellae fixae) are the luminary points, mainly stars, that appear not to move relative to one another against the darkness of the night sky in the background. This is in contrast to those lights visible to naked eye, namely planets and comets, that appear to move slowly among those "fixed" stars. The fixed stars includes all the stars visible to the naked eye other than the Sun, as well as the faint band of the Milky Way.
Crab NebulaThe Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant and pulsar wind nebula in the constellation of Taurus. The common name comes from William Parsons, 3rd Earl of Rosse, who observed the object in 1842 using a telescope and produced a drawing that looked somewhat like a crab. The nebula was discovered by English astronomer John Bevis in 1731. It corresponds with a bright supernova recorded by Chinese astronomers in 1054 as a guest star.
Cardinal directionThe four cardinal directions, or cardinal points, are the four main compass directions: north, south, east, and west, commonly denoted by their initials N, S, E, and W respectively. Relative to north, the directions east, south, and west are at 90 degree intervals in the clockwise direction. The ordinal directions (also called the intercardinal directions) are northeast (NE), southeast (SE), southwest (SW), and northwest (NW). The intermediate direction of every set of intercardinal and cardinal direction is called a secondary intercardinal direction.
Star chartA star chart is a celestial map of the night sky with astronomical objects laid out on a grid system. They are used to identify and locate constellations, stars, nebulae, galaxies, and planets. They have been used for human navigation since time immemorial. Note that a star chart differs from an astronomical catalog, which is a listing or tabulation of astronomical objects for a particular purpose. Tools utilizing a star chart include the astrolabe and planisphere.
