Astronomy: Ancient Astronomy

From Astronomy Encyclopedia
Astronomical treatise composed in c.AD 140 by Ptolemy. It summarizes the astronomy of the Graeco-Roman world and contains a star catalogue and rules for calculating future positions of the Moon and planets according to the Ptolemaic System.

Study of the relative position of the planets and stars in the belief that they influence events on Earth. A strongly held belief in ancient Babylon, astrology spread to the Mediterranean world, and was widely used by the Greeks and Romans.

System of reckoning time for the practical purpose of recording past events and calculating dates for future plans. The calendar is based on noting ordinary and easily observable natural events, the cycle of the sun through the seasons with equinox and solstice, and the recurrent phases of the moon.

From The American Heritage Science Dictionary
In Ptolemaic cosmology, a small circle representing a temporary adjustment to the position of a planet as it orbits the Earth.

From The Penguin English Dictionary
A fixed projecting part that casts a shadow on the face of a sundial, indicating allowing the time to be told.

From The Columbia Encyclopedia
Historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with all celestial bodies revolving around it (see cosmology).

From The Hutchinson Unabridged Encyclopedia
Prehistoric megalith. The circles were built with standing stones, usually on level ground. Many are now partly fallen or incomplete, the stones having been removed for building.

Instrument that indicates the time of day by the shadow, cast on a surface marked to show hours or fractions of hours, of an object on which the sun's rays fall.

From The Hutchinson Unabridged Encyclopedia
Arabian scientist. He was the author of the Kitab al-Manazir/Book of Optics, translated into Latin as Opticae thesaurus (1572). For centuries it remained the most comprehensive and authoritative treatment of optics in both East and West.

Greek mathematician, physicist, and inventor. He is famous for his work in geometry (on the circle, sphere, cylinder, and parabola), physics, mechanics, and hydrostatics.

From Science in the Ancient World: An Encyclopedia
Aristarchus of Samos was a mathematician who was the first human to argue that the sun, not the earth, was the center of the universe. Aristarchus was a theorist more than an empiricist.

From Britannica Concise Encyclopedia
Indian mathematician and astronomer who wrote three astronomical treatises, only one of which, the Āryabhatīya (AD 499), survives.

From Chamber's Biographical Dictionary
Born in Wan (Nanyang), he was the astronomer royal at the court of the later Han emperors. Although none of his actual works has survived there are detailed accounts extant of several of his inventions.

From Science in the Ancient World: An Encyclopedia
Eudoxus, Pythagorean and student of Plato, was an astronomer, mathematician, and physicist. He wrote Phaenomena, one of the seminal statements from the ancient world on astronomy.

From Science in the Ancient World: An Encyclopedia
Heraclides was an astronomer of note and the first known to speculate that at least some planets orbit the sun. He was a student of the Academy and was influenced by both Plato and Aristotle.

From Astronomy Encyclopedia
Greek astronomer, geographer and mathematician who made observations from Nicea (in what is now modern Turkey), Alexandria, Egypt and the Greek island of Rhodes.

From The Columbia Encyclopedia
The Persian poet, astronomer and mathematician lived at Nishapur, where he died at about the age of 50 in about ad 1123.

Greek astronomer, mathematician, and geographer. His Geography was the standard geographical textbook until the discoveries of the 15th century.