Superior Ptolemaic Model
written by Todd Timberlake
The Ejs Superior Ptolemaic model illustrates Ptolemy's orbit for a superior planet. The model consists of a deferent circle, centered on a point some distance from Earth (at the eccentric point). Attached to this deferent is the center of another circle, the epicycle. The center of the epicycle moves around the deferent with constant angular speed as seen from the equant point, which is exactly opposite the center of the deferent from Earth (so the center of the epicycle does not move at constant speed along the deferent). The planet moves along the epicycle at constant speed. This model is capable of reproducing retrograde motion and variations in the planet's brightness. It can also reproduce variations in the apparent size and spacing of the retrograde arcs. In this simulation the planet is assumed to move in the plane of the ecliptic, so its latitude is always zero. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item.
Ejs Superior Ptolemaic model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_SuperiorPtolemaic.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for astronomy are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.
Please note that this resource requires at least version 1.5 of Java (JRE).
View the supplemental document attached to this resource
View the source code document attached to this resource
ComPADRE is beta testing Citation Styles!
Disclaimer: ComPADRE offers citation styles as a guide only. We cannot offer interpretations about citations as this is an automated procedure. Please refer to the style manuals in the Citation Source Information area for clarifications.
Citation Source Information
The APA Style presented is based on information from APA Style.org: Electronic References.
The Chicago Style presented is based on information from Examples of Chicago-Style Documentation.
The MLA Style presented is based on information from the MLA FAQ.
Superior Ptolemaic Model:
Is Based On Easy Java Simulations Modeling and Authoring Tool
The Easy Java Simulations Modeling and Authoring Tool is needed to explore the computational model used in the EJS Superior Ptolemaic Model.relation by Mario Belloni
Supplements Simple Fictitious Solar Systems
Is Supplemented By Physlet Physics 2E: Illustration 12.6: Heliocentric vs. Geocentric
Know of another related resource? Login to relate this resource to it.
Is Based On