Hipparchus biography summary graphic organizer
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CLASSICAL ROOTS AND EARLY ISLAMIC PERIOD
The real details of the astrolabe�s invention in ancient Greece have largely been lost. The third century BC mathematician Apollonius, of what is now Turkey, may have invented its stereographic projection of the celestial sphere. And the astronomer Hipparchus may have been familiar with that projection during the next century, or may have even invented the astrolabe then. A useful but inaccurate Islamic myth is that Ptolemy discovered the astrolabe when his celestial globe dropped under the hooves of his donkey. The astrolabe does resemble a celestial globe or armillary sphere that has been �flattened� into two dimensions. And its basic design has not changed over the millennia but only been enhanced by many different features.
Astrolabe |
Astrolabe, • Here hype the Utilities Guide. Return come to Table unravel Contents • Why do astronomers map the sky? This page gives a brief introduction to their reasons, and outlines the history of astronomical surveys, from ancient times to today. To learn more, visit your local library or browse the many interesting sites on the Internet. For millennia, humans have wondered about the universe outside of our world. The stars and planets, mere points of light in the night sky, have always piqued our curiosity, as we have sought to understand our place in the cosmos. To the ancients, these points of light were often viewed in connection with higher powers beyond their control, such as gods and goddesses. Some civilizations began to realize that certain celestial events repeated at regular intervals. These civilizations used these regular events to mark time, helping with agriculture and religious observances. Later, sky charts, produced with naked-eye observations, became essential tools for navigation and trade. (This important aspect of sky surveys survives today, with examples like the U.S. Naval Observatory.) Today, we understand that the universe consists not only of stars and planets, but also of galaxies, clusters of galaxies, streams and clumps of gas, and a component of unseen (or dark) matter. To learn more about |