Across
- 2. A measure of how large an object looks to you
- 4. Half the long dimension of an ellipse
- 6. The shift in an object's position caused by the observer's motion
- 7. Models of the solar system centered on the Earth
- 10. A geometric figure related to a circle but flattened into an oval
Down
- 1. A body orbiting a planet
- 3. The drift of a planet westward against the background stars
- 5. Models of the solar system centered on the Sun
- 8. A fictitious, small, and circular orbit superimposed on another circular orbit and proposed by early astronomers to explain the retrograde motion of the planets
- 9. One of two points within an ellipse used to generate the elliptical shape