Planets

1. A point directly overhead from an observer
5. The apparent change in position of two objects viewed from different locations
7. The angle between a body's equatorial plane and orbital plane
8. The point in the orbit of a planet
9. Sixth planet from the sun
11. Named after goddess of love & beauty
12. Brightness differences used in astronomy
13. A glow in a planet's ionosphere caused by the interaction between the planet's magnetic field
16. The amount of matter contained within a given volume

2. A cloud of dust and gas in space
3. The red planet
4. The passing into the shadow of a celestial body
6. Person who studies stars & moons
10. The angular distance of an object above the horizon
14. The area of total darkness in the shadow caused by an eclipse
15. The surface of the Sun or other celestial body projected against the sky