Astronomy Vocabulary

4. a group of stars with fixed distances between them, that typically resembles a pattern of picture
6. First to calculate circumference of earth
8. Improved the spyglass and used it to discover the 4 moons of Jupiter, phases of Venus, and found the Milky Way was made of many, many stars
9. The imaginary line on which the Sun, Moon, and planets travel
13. Motion The perceived revers motion of a planet in the sky; caused by Earth passing another planet in its orbit
16. An imaginary sphere surrounding the earth on which all galaxies, stars, and nebula revolve.
17. A great circle on the celestial sphere 90° from the zenith; the place where the sky meets Earth

1. A great circle on the celestial sphere 90° from the celestial poles; where the celestial sphere interacts with the plane of Earth’s equator
2. First to create a catalogue of stars by brightness
3. Centered on the Sun
5. A measure of how bright a star looks in the sky; the larger the number, the dimmer the star appears to us
7. The circular orbit of a planet in the Ptolemaic system, the center of which revolves around another circle(the deferent)
10. The slow movement of Earth’s celestial North Pole in an elliptical 26,000 year cycle - caused by the gravitational pull of the Moon and Sun on Earth’s equatorial bulge
11. The point on the celestial sphere opposite the direction of gravity; the point directly overhead
12. The movement of nearby stars throughout the year that results from the motion of Earth around the Sun
14. Centered on earth
15. First to present the heliocentric model