When to use the Geocentric vs Heliocentric 3D Explorer
Open the Geocentric vs Heliocentric 3D Explorer when you need to contrast the Ptolemaic (Earth-centered) and Copernican (Sun-centered) MODELS side by side, using the same real Earth/Mars orbits (Earth 1 AU, Mars 1.52 AU, Mars synodic period about 779.9 days) - not just watch the retrograde loop by itself.
A five-minute classroom demo
A five-minute classroom demo starts when you open the Geocentric vs Heliocentric 3D Explorer in the Ptolemaic view, press Play, and switch to the Copernican view mid-loop so students see the SAME Mars positions re-centered on the Sun instead of Earth.
Geocentric vs Heliocentric 3D Explorer vs the Retrograde Motion 3D Explorer
The Geocentric vs Heliocentric 3D Explorer and the Retrograde Motion 3D Explorer share the same underlying orbits but answer different reader tasks: Retrograde Motion 3D Explorer shows the optical effect from Earth's viewpoint only, while Geocentric vs Heliocentric 3D Explorer contrasts the two historical MODELS that explain it - a history-of-science task, not just an observational one.
Sessions the Geocentric vs Heliocentric 3D Explorer does not fit
Sessions the Geocentric vs Heliocentric 3D Explorer does not fit are ones that need Ptolemy's actual historical epicycle/deferent circle radii for Mars - no single verifiable figure for those parameters exists, so the scene re-centers the real orbits on Earth instead and discloses this explicitly. Walk the controls in the step-by-step guide.
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