The Ptolemaic Astronomy

THE PTOLEMAIC ASTRONOMY

Ptolemy was an astronomer whose work was acknowledged around 150 AD. He was really interested in the “problem of the planets” which translates to the word “Ptolemy Astronomy” itself(Kuhn, pg-66). Ptolemy astronomy flourished in the era of when the earth was assumed to be the center of the universe rather than the sun. Copernicus brought about the argument of the sun. Ptolemy presented his astronomical models in convenient tables to record the positions of the planet and findings (Kuhn, ph-70). This was one of the reasons why his work was greatly appreciated by his successors as well as taken as reliable. He first acknowledged the fact that the ancient astronomers even though had accounted for the movement, position and pattern of the sun, the moon, the stars and other celestial objects like comet; could not account for the irregular rate of motion of the planets (be it major or minor)(Kuhn, pg-50).

Therefore, after significant data gathering Ptolemy came to the conclusion, which let to the Ptolemaic theory regardless of the fact that it was just the starting point of planetary observation. Ptolemy was a major influence on Copernicus and other philosophers such as Apollonius and Hipparchus (Kuhn, pg-72) (discussed below). The Ptolemaic model has 4 major components or devices that builds up the theory:

1. Epicenter- “with earth being the center of the geometric sphere, the planet is positioned in a small circle that rotates uniformly about a point on the circumference of a second rotating circle, the deferent” taken from the Copernican Revolution by Thomas S. Kuhn. Therefore, it suggests that a planet set along the surface of a circle with earth being the center, moves in another circle motion of its own which is called the epicenter.

2. Deferent- Deferent is a circle that forms the circumference around the earth; with earth with the focal point. The planet is positioned in the deferent while it moves in a circular motion on the...