HISTORICAL ASTRONOMERS

ARISTOTLE

• He thought earth was in the center of all things
• He created parallax

ARISTARCHUS

• He proposed a heliocentric solar system
• He tried to measure the distance of the stars to earth which contributed

Ptolemy
He contributed by writing a book which is about observing planets.
He said a celestial body traveled in a perfect circle.

Copernicus
He developed the first detailed heliocentric model.
He also thought planets move in a perfect circle

Kepler
He discovered that planets did not move in a perfect circle. He thought planets moved in ellipses.

Galileo Galilei
Improved the telescope. He discovered Venus went through phases similar to the moon