Ptolemy Essays - Ancient Greek Mathematicians, Claudii,

Ptolemy Introduction In ancient times there were many great ideas which began to shape the way man perceived his environment. However, there were few minds who were able to put all of these ideas together. One of these minds belonged to Claudius Ptolemy, or just Ptolemy as he is commonly referred to. We know almost nothing of the chronology of Ptolemy's life, and we don't even know his birth or death dates. We do know, though, about his ideas in several fields, which include geography, astronomy, optics, astrology, music, and other topics. His most profound and lasting contributions came in the fields of geography and astronomy, where his two written works Geography and Almagest dominated the thinking on these subjects throughout ancient times and for many centuries to follow. To geographers, Geography represented a breakthrough in the spatial tradition of geography through Ptolemy's principles on cartography and the maps that were created from this. This will be reviewed as well as other aspects of Ptolemy's work that made him such a respected figure in the history of geography. Astronomy and Almagest It is important to mention the impact that Ptolemy had in the field of astronomy, as it allows us to understand the ideas that he was able to bring to geography. Ptolemy did his astronomical observations in Alexandria, Egypt, and it has been estimated by scholars that his findings were made in 150 AD After recording his observations and analyzing them, he incorporated them into a work that would be called the Almagest, which is a combined Greek and Latin term meaning "the greatest". Almagest is revered as one of the top astronomical works of all time, as it was a thirteen book mathematical treatment of the phenomena of astronomy. It contains a myriad of information ranging from earth conceptions to sun, moon, and star movement as well as eclipses and a breakdown on the length of months. Among his astronomical observations were the idea that the earth did not move, but rather it was the motionless center of the universe with the sun, moon, planets, and stars revolving around it. Another of Ptolemy's ideas was that the planets were closer to the earth than the stars, but farther away than the moon (which is true). These and other ideas were accepted as scientific fact for several centuries following the writing of Almagest. In fact, these ideas weren't changed or corrected until the findings of Copernicus in 1543. Geography Although we don't know if Geography was written before or after Almagest, it remains a trivial side note compared to geographical concepts presented in it that draw the interest of geographers. The introduction to Geography states what Ptolemy wants to accomplish, which includes an explanation of the principles of cartography such as giving coordinates to places around the world and geographic features as well as recommendations for making world and regional maps. He then starts his coverage of the world with Europe in Books 2 and 3. He goes on to cover Africa in Book 4 and covers Asia and summarizes his findings in Books 5-8. Geography included 26 colorized regional maps as well as one map of the "known world". Ptolemy stayed away from orthogonal (or cylindrical) world mapping in favor of three other projection types. He returns to orthogonal projection on some regional maps with dimensions based on mean latitude. The farthest point north on his map was Thule at 63 degrees north, while the farthest point south was the Agysimba and Prasum promontory east of Africa at 16 degrees, 25 minutes south. He measured the north-south length of the known world to be about 7392 kilometers or 4580 miles, while his east-west measurement was about 13,306 kilometers or 8250 miles. Geography held the same respect in the field of geography that Almagest had in astronomy. Geography was regarded as a complete and inerrant document on the subject of geography, and it dominated geographical theory until the Renaissance. The Almagest is now regarded as a better document than Geography scientifically. This is because the application of the concepts presented in Geography was substantially limited, although advances in geography theory were made. Actions After Geography Ptolemy's work has been discovered and used through the ages by several noted people around the world. Arabic writer al-Mas'udi, while writing around 956, mentioned a colored map of the Geography which had 4530 cities and over 200 mountains. Byzantine monk Maximus Planudes found a copy of the Geography in 1295, and since there were no maps in his copy, he