A Greek Astronomer for All Seasons

We are bounded in a nutshell of Infinite Space: Free Form #7: A Greek Astronomer for All Seasons

Previously, we have been looking at various Greek myths which illustrated how these viewed the stars and themselves, reflections of the heavens. However, there would be those to go beyond the limited scope of religion and culture, and push to truly understand the stars above them. First off, we have Hipparchus, possibly the greatest astronomer of the Ancient World. One of his largest contributions was the establishment of the system we still use to classify the brightness of stars and other objects: magnitudes. As intricate and complicated as this system may be, it was the first major attempt to organize the objects observed in the night sky, with which Hipparchus was able to create the largest star catalog in the Ancient World. Besides this, Hipparchus would go on to establish the nature of equinoxes and solstices, and accurately measure the movements of the Sun and Moon, which further allowed him to understand seasons and how they occurred. Hipparchus even began establishing the basis for astronomy throughout the next couple of thousand years by attempting to measure the distance to the Moon using stellar parallax. These systems were also integral to another component of his work, the development of trigonometry.  

Hipparchus
http://www.nndb.com/people/842/000103533/hipparchus-1-sized.jpg

Another interesting astronomer of the time was Eratosthenes, the man who effectively calculated the size of the Earth, created the discipline of geography, as well as being the chief librarian of the Library of Alexandria. By moving to different places across Egypt, Eratosthenes measured the differences in the elongating of a shadow, using this to create a model of a sphere which had the curvature he had measured due to the change in shadow length. From this, he extracted a proportion and accurately found the size of the Earth. Furthermore, he would go on to attempt to measure the size of the Sun, using techniques which would be imprecise with his tools, but necessary for future astronomers to effectively find this value. He, quite literally, created Geography, the science of measuring and describing the terrain of the Earth. Sadly, most of his works were destroyed in the Burning of the Library of Alexandria, but the few texts that remain and are cited by other authors tell of a man with an unsociable pursuit of knowledge.

Eratosthenes
http://web.jccc.edu/gallery/astrotext/Bills%20Files/Astronomy%20Textbook/Chapter%203_files/img2sdf.gif

These men were but two of a great tide of ancient scientists who defined the physical world for millennia, until science began to develop in the second millennium and once again the early remarks made by these astronomers were reinterpreted and researched further than they ever could have.