1. The constellation that contains Polaris is ? Ursa Minor
2. The constellation that contains the pointer stars is ? Ursa Major
3. A large group of stars revolving around a center is known as a ? galaxy
The Milky Way is an example of a ? galaxy
4. A first magnitude star is ? 2.5 times as bright as a second magnitude star
5. The expression "first magnitude" is usually used to refer only to bodies of magnitude ? 1.5 and greater
6. The dimmest stars that could be used for navigational purposes are of what magnitude? Third
7. Under ideal viewing conditions, the dimmest star that can be seen with the unaided eye is of what magnitude ? Sixth
8. A star that suddenly becomes several magnitudes brighter and then gradually fades is a ? nova
9. A variable star is one that ? exhibits a change in magnitude
10. A double star is a star that ? comprises two stars that appear close together
11. The major factor that causes the color difference between a red star (Betelgeuse) and a blue star (Rigel) is ? its surface temperature
12. Planetary aberration is due, in part, to ? the body's orbital motion during the time required for its light to reach Earth
13. Diurnal aberration is due to ? rotation of the Earth on its axis
14. Inferior conjunction is possible for ? Mercury
15. Inferior conjunction is possible for ? Venus
16. Superior conjunction occurs when ? the Sun is between the Earth and a planet
17. As observed from the Earth, the angle between lines from the Earth to the Sun and the Earth to an inferior planet is known as ? elongation
18. Elongation becomes zero at ? inferior conjunction
19. The parallel of latitude at 66°33 N is the ? Arctic Circle
20.The parallel of latitude at 23°27 S is the ? Tropic of Capricorn
