Lab Exercises in Astronomy: The Orbit Of Mars
The orbit of Mars is far more elliptical than Earth's. But it's a mistake to think that it looks like an oval - it looks more like a circle that is off-centered from the Sun. Teach your students the concept of elliptical orbits by having them calculate the ellipticity of Mars's orbit and draw it out. Astrophysicist and Harvard professor Owen Gingerich wrote this classic astronomy lab exercise.