| 11. | In the Hipparchian system the epicycle rotated and revolved along the deferent with uniform motion.
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| 12. | Deferents and epicycles in the ancient models did not represent orbits in the modern sense.
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| 13. | That seems to contradict Deferent and epicycle.
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| 14. | A Spirograph pattern is just one epicycle.
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| 15. | Copernicus eliminated Ptolemy's somewhat-maligned equant but at a cost of additional epicycles.
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| 16. | Various 16th-century books based on Ptolemy and Copernicus use about equal numbers of epicycles.
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| 17. | Ptolemy described lunar motion by using a well-defined geometric model of epicycles and evection.
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| 18. | epicycles using the Tusi-couple, thus eliminating the Ptolemaic eccentrics and equant . ]]
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| 19. | :: : That article states that retrograde motion was used to develop the epicycles system.
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| 20. | Astronomers responded by introducing the deferent and epicycle, which caused a planet to vary its distance.
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