This lecture can be used as for college level students.
To continue with the understanding of Kepler’s laws, the presentation is a build up of the Physical-Mathematical concepts of the 2-Body problem and reduced mass. It culminated with the deduction of the total energy for the reduced mass system. The results will be used in a future lecture about the orbital angular momentum, and in a later discussion of the second and third laws of Kepler.
Lecture
http://www.showme.com/sh?h=pkdypyS
Addendum
AstroDidactics 