early late greek astronomers

refers to astronomy written in the Greek language in classical antiquity. Greek astronomy is understood to include the ancient Greek, Hellenistic, Greco-Roman, and Late Antiquity eras.
Greek astronomy is characterized from the start by seeking a rational, physical explanation for celestial phenomena.[1] Most of the constellations of the northern hemisphere derive are taken from Greek astronomy,[2] as are the names of many stars and planets. It was influenced by Babylonian and, to a lesser extent, Egyptian astronomy; in turn, it influenced Indian, Arabic-Islamic and Western European astronomy.

thales
Thales of Miletus (Θαλῆς ὁ Μιλήσιος)
(one of the Seven Sages of Greece.)

first to define general principles and set forth hypotheses, and as a result has been dubbed the "Father of Science".[3][4]Thales' most famous belief was his cosmological thesis, which held that the world started from water. Thales applied his method to objects that changed to become other objects, such as water into earth (he thought). Theorem of Thales, one having to do with a triangle inscribed in a circle and having the circle's diameter as one leg, the other theorem being also called the intercept theorem.) The most natural epithets of Thales are "materialist" and "naturalist", which are based on ousia and physis. Some believe Anaximander was a pupil of Thales. Early sources report that one of Anaximander's more famous pupils, Pythagoras, visited Thales as a young man, and that Thales advised him to travel to Egypt to further his philosophical and mathematical studies.Thales studied mathematics and claimed that the Earth was spherical in shape.


Philolaus
Philolaus (Greek: Φιλόλαος; c. 470–c. 385 BCE[1])

He is credited with originating the theory that the earth was not the center of the universe.One of the works of Philolaus was called On Nature,[13] which seems to be the same work which Stobaeus calls On the World, and from which he has preserved a series of passages. Philolaus says that there is fire in the middle at the centre ... and again more fire at the highest point and surrounding everything.the sky, the planets, then the sun, next the moon, next the earth, next the counterearth, and after all of them the fire of the hearth which holds position at the centre.A popular misconception about Philolaus is that he supposed that a sphere of the fixed stars, the five planets, the Sun, Moon and Earth.Philolaus regarded the soul as a "mixture and harmony" of the bodily parts; he also assumed a substantial soul, whose existence in the body is an exile.

Eratosthenes
Eratosthenes of Cyrene (Greek Ἐρατοσθένης, pronounced er-ə-TOS-thə-neez; c. 276 BC[1] – c. 195 BC[2])
He was a Greek mathematician, astronomer, athlete, poet, and librarian at the ... You can try out Eratosthenes' method to discover all the prime numbers ...Eratosthenes Project. This project is named for the Greek astronomer who accurately estimated the circumference of the Earth. It is described in LabNet:
He was the first person to use the word "geography" and invented the discipline of geography as we understand it.[3] He invented a system of latitude and longitude.

Anaximander


Hipparchus Greek Astronomer
Considered Greatest Ancient Astronomical Observer

hipparchus
he is mainly credited for precession, the compilation of the first comprehensive Star Catalogue. He also drew the first accurate star map with more than 1,000 stars that were divided into orders based on their brightness; the fundamentals of this system are in use today.

Cleomedes
Cleomedes (Κλεoμήδης) was a Greek astronomer who is known chiefly for his book On the Circular Motions of the Celestial Bodies.


Cleomedes book is known is a fairly basic astronomy textbook in two volumes.(Cleomedes appears to have been a dedicated Stoic).Cleomedes is accurate in some of his remarks on lunar eclipses, especially his conjecture that the shadow on the Moon suggests a spherical Earth. He also remarks presciently that the absolute size of many stars may exceed that of the Sun (and that the Earth might appear as a very small star, if viewed from the surface of the Sun).

Pythagoras of Samos
about 569 BC - about 475 BC

Pythogoras proposed that the Universe was made of concentric spheres surrounding the Earth, the sun, moon and planets each travelled in their own sphere.

Eudoxus of Cnidus

(c400 355BC)
he taught that the heavens revolved around the earth, which was the centre of the universe but added to Pythogorian system by adding more spheres to account for the irregular movements of the planets and the moon. He mapped the stars and compiled a map of the known world. His philosophy influenced Aristotle.

Aristotle
he showed that the Earth was a sphere but thought that the Earth was the centre of the universe because he couldn't see the stars shift position thru the year. (The stars are too far away to see their movement in a short period of time).

Aristarchus
(c 200s BC)
he held an opposite theory, he showed that certain movements of the sky could be explained by assuming that the earth moved around the sun. The important ideas of early astronomy were developed by Greek scholars during the 400 years before the birth of Christ.

Hipparchus
(c 100s BC)
he carefully recorded the positions of stars, the sun, and the moon. His work was so complete that other astronomers used it to predict eclipses of the sun and the moon. He accurately measured the distance from the Earth to the Moon, completed the first known star catalogue and developed the magnitude system for comparing star brightness. He also discovered precession - the slow wobble of the Earth's axis caused by the gravitational pull of the sun and moon. Hipparchus measured the distance from the Earth to the Moon during a solar eclipse that was a total eclipse at Syene and a partial eclipse at Alexandria.he also measured the precession of the Earth's rotation axis.

Claudius Ptolemy
About AD 150
Claudius Ptolemaeus published a book based on the work of Hipparchus. Ptolemy was a Greek astronomer working in Egypt. In his book he strengthened the idea that the earth was the centre of the universe. The book became highly respected, and it firmly established his theory among Greek and Arab astronomers. Gradually, European scholars learned about Ptolemy's work from the Greeks and the Arabs. For more than a thousand years no one seriously questioned Ptolemy's theory.

Nicholas Copernicus
(1473 - 1543)
he was largely responsible for advancing astronomy beyond the ideas of Ptolemy and others. A member of the Church and studying astronomy and mathematics, he was unhappy with the many errors in the system of Ptolemy and decided to revise those ideas by placing the sun at the centre of the Universe with the Earth and other planets orbiting around it.

Tycho Brahe
(1546 - 1601)
he accepted Copernicus ideas and set out to make accurate observations of the skies. Working on the Baltic island of Hven he built an observatory (the Castle of Uraniborg) where he gathered a large amount of accurate observations which led to the development of a model where the planets orbit the sun but the sun orbits a stationary Earth. Tycho's model did not gain wide spread acceptance but an assistant of Tycho's - Johnnes Kepler (1571 - 1630) continued Tycho's work but found great difficulty fitting the orbit of Mars into a circular orbit, he therefore abandoned the circular orbit and substituted the ellipse thereby fitting the observations taken of Mars.

Zacharias Jansen
In 1590 a Dutchman
Zacharias Jansen designed the first telescope and in 1608 Jan Lippershey manufactured the first usable telescope. Galileo Galilei (1564 - 1642) modified a Jansen-Lippershey telescope to look at the sky, his discovery of craters and mountains on the moon, the four large satellites of Jupiter, sunspots and phases of Venus, amazed astronomers but due to religious opposition Galileo was placed on trial by the Church and found guilty of teaching Copernican theory. He was forced to renounce his astronomical findings.

Isaac Newton
(1642 - 1727)
he used mathematics to work out planetary motions and developed the theory of universal gravitation - the action of gravity which works throughout the Universe. Newton's model put astronomy on a firm footing making it possible to accurately predict the motion of the planets around the sun.

Sir William Herschel
(1738 - 1822)
he constructed a 40 foot long telescope and with it discovered the first of the modern planets Uranus in 1781 as well as about 5,000 nebulae, stars and planetary nebula.

Johann Galle
(1812 - 1910)
he discovered Neptune in 1846 as a result of calculations by Urbain Leverrier (1811 - 1877). At the same time John Couch Adams (1819 - 1892) independently also calculated the position of Neptune. Percival Lowell (1855 - 1916) predicted that a planet must exist beyond the orbit of Neptune in 1905

It wasn't until 1930 that C. W Tombaugh working at the Lowell Observatory in Arizona USA discovered the last of the modern planets - Pluto. In 1978 it was discovered that Pluto has a satellite - Charon. Visiting probes and greatly enhanced telescopes continue to find satellites orbiting the large planets far from our sun.

Aristarchus
lived from about the year 310 before the present era to about 230,

aristarchus’ only extant treatise is “On the Sizes and Distances of the Sun and Moon.” In it he calculated the diameter of the Sun as about seven times the diameter of the Earth, thus estimating the Sun’s volume as about 300 times the volume of the Earth

Nicolaus Copernicus
1473 - 1543

Copernicus was a Polish astronomer and mathematician who was a proponent of the view of an Earth in daily motion about its axis and in yearly motion around a stationary sun.