Astronomical Figures

Oenopides

450 BCE

Oenopides was an astronomer of ancient Greece, born on the Island of Chios at around 450 BC. His greatest accomplishment was determining the angle of the sun relative to the earth; His twenty-six degree measure remained the standard until Eratosthenes measured it with more accuracy, hundreds of years later.

Bion of Abdera

430 BCE

Bion of Abdera was a Greek Astronomer born in the city of Abdera, who was the first two postulate that there were parts of the earth where it was night for six months and day for the other six.

Euxodus of Cnidus

390 BCE

Euxodus was an ancient Greek mathematician and astronomer, who was born and died in the city of Cnidus. He contributed one of the earliest models of planetary motion, which, though inaccurate, was widely accepted throughout the scientific community at the time.

Eratosthenes

276 BCE

Eratosthenes was a Greek philosopher and astronomer who calculated the circumference of the earth, as well as the axial tilt of the earth; further refining the centuries old calculations of Oenopides of Chios

Hipparchus

190 BCE

Hipparchus was a Greek astronomer from the city of Nicaea, who is often called the father of modern astronomy. He was the first to predict solar eclipses, created the astrolabe, trigonometry, and accidentally discovered the existence of equinoxes.

Menelaus of Alexandria

70

Menelaus of Alexandria was a Grecian mathematician and astronomer, who discovered the occlusions of two stars by the moon, and used that to confirm Hipparchus' discovery of the equinox.

Ptolemy

100

Claudius Ptolemy was a Greek astronomer and Roman citizen who wrote the most widely accepted treatise on astronomy of his day, showing thousands of stars in charts; as well as documenting equinoxes. However, modern scientists have gone over his Almagest and have accused him of fabricating his data to support his assumptions, and doctoring the data of other astronomers. He has been called the most successful fraud in history.

Zhang Heng

120

Zhang Heng was a Chinese astronomer and statesman who lived during the Han Dynasty. He explained the nature of the reflective light of the moon, as well as the cause of eclipses.

Tycho Brahe

1546

Tycho Brahe was a Danish astronomer of the Renaissance, and the first to document a supernova, which he assumed was the birth of a star; he was quite wrong, however, the phenomenon rather being the death of a star.

Edmond Halley

1690

Edmond Halley was an English astronomer, mathematician and physicist who calculated the distance between earth Venus, and the Sun based on the length of the orbits. He also calculated the periodicity of Halley's comet, using Isaac Newtons laws of universal gravitation; The comet was named after him on it's predicted return, which he did not live to see.