Unformatted text preview: Models of the Sky - Celestial Sphere All of the motions that I went through are pretty complex, and they all need to be explained, so that you can predict the motions, so that you can set up some sort of calendar system, so that you'll know when to celebrate your various festivals and celebrations or when to plant or harvest your crops, or, well, whatever you need to know. To explain all of these motions, early astronomers/astrologers needed to figure out the mechanics of the sky - they needed a model (something that could explain the motion; not necessarily a physical model, but at least something that they could write down). Since the motions of the stars are fairly uniform, the model for their motions is easiest to do and we'll tackle it first. One of the concepts that people believed in the old days was that the stars (and everything else in the sky) were moving and the Earth wasn't. This sort of made sense, mainly because people did not feel any motions from the Earth - they had no sense that it was...
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- Fall '10
- Astronomy, Rotation, celestial pole, Pole star