Download the original video from
http://www.astronomy.ohio-state.edu/~pogge/Ast161/Movies/
This movie shows the motions of the solar system from 1543 until late 1550 AD as seen from above the ecliptic plane. Two perspectives are shown:
1. The perspective of a fixed earth, showing how the motions appear from a geocentric view point. Please note that this is not a realization of the Ptolemaic System proper: we are computing actual solar system motions seen from the reference frame of the earth.
2. The perspective of a fixed sun, showing how the motions appear from a heliocentric view point. Again, this is not strictly the “Copernican” model as proposed in De Revolutionibus, as we are using computed actual motions, not a realization of the complex system of heliocentric epicycles proposed by Copernicus.
The first segment traces out the path of the Sun and Mars, showing Mars through one evolution of its retrograde motion as seen from the Earth. From this “geocentric” perspective, the true orbital paths of Venus and Mercury trace out complex looping motions. The second segment begins by stopping the motion, erasing the paths, and then shifting to the heliocentric perspective. We then watch the evolution of the orbits of the 4 inner planets (Mercury, Venus, Earth, and Mars) through one Martian siderial period (1.52 years), and the zoom out and view the orbits of the outer two of the 5 naked-eye planets, Jupiter and Saturn.
The orbital motions in both segments are the same, only the point of view (fixed-earth vs. fixed-sun) has changed.
The point of this movie is to show how complex the paths appear from the perspective of a moving Earth, and how much simpler they become when we shift our perspective to that of a fixed Sun.
Movie by Rick Pogge (OSU Astronomy), using Starry Night Pro (v3.0.2)
Post time: Jun-16-2017