Celestial mechanicsCelestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data. Modern analytic celestial mechanics started with Isaac Newton's Principia of 1687. The name "celestial mechanics" is more recent than that. Newton wrote that the field should be called "rational mechanics.
Chinese astronomyAstronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 xiù) system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE).
AryabhataAryabhata ( ISO: ) or Aryabhata I (476–550 CE) was the first of the major mathematician-astronomers from the classical age of Indian mathematics and Indian astronomy. His works include the Āryabhaṭīya (which mentions that in 3600 Kali Yuga, 499 CE, he was 23 years old) and the Arya-siddhanta. For his explicit mention of the relativity of motion, he also qualifies as a major early physicist.
AstrologyAstrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Different cultures have employed forms of astrology since at least the 2nd millennium BCE, these practices having originated in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications.
Lunar nodeA lunar node is either of the two orbital nodes of the Moon, that is, the two points at which the orbit of the Moon intersects the ecliptic. The ascending (or north) node is where the Moon moves into the northern ecliptic hemisphere, while the descending (or south) node is where the Moon enters the southern ecliptic hemisphere. A lunar eclipse can occur only when the full Moon is near either lunar node (within 11° 38' ecliptic longitude), while a solar eclipse can occur only when the new Moon is near either lunar node (within 17° 25').
Prutenic TablesThe Prutenic Tables (Tabulae prutenicae from Prutenia meaning "Prussia", Prutenische oder Preußische Tafeln), were an ephemeris (astronomical tables) by the astronomer Erasmus Reinhold published in 1551 (reprinted in 1562, 1571 & 1585). They are sometimes called the Prussian Tables after Albert I, Duke of Prussia, who supported Reinhold and financed the printing. Reinhold calculated this new set of astronomical tables based on Nicolaus Copernicus' De revolutionibus orbium coelestium, the epochal exposition of Copernican heliocentrism published in 1543.
Celestial navigationCelestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the surface of the Earth without relying solely on estimated positional calculations, commonly known as "dead reckoning." Celestial navigation is performed without using satellite navigation or other similar modern electronic or digital positioning means.
Julian dayThe Julian day is the continuous count of days since the beginning of the Julian period, and is used primarily by astronomers, and in software for easily calculating elapsed days between two events (e.g. food production date and sell by date). The Julian period is a chronological interval of 7980 years; year 1 of the Julian Period was 4713 BC (−4712). The Julian calendar year is year of the current Julian Period. The next Julian Period begins in the year AD 3268.
HoroscopeA horoscope (or other commonly used names for the horoscope in English include natal chart, astrological chart, astro-chart, celestial map, sky-map, star-chart, cosmogram, vitasphere, radical chart, radix, chart wheel or simply chart) is an astrological chart or diagram representing the positions of the Sun, Moon, planets, astrological aspects and sensitive angles at the time of an event, such as the moment of a person's birth. The word horoscope is derived from the Greek words ōra and scopos meaning "time" and "observer" (horoskopos, pl.
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.