# Astronomy Unit One Part I

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1. How many constellations are always above Cinci?
59
2. Planisphere times:
Current
EST
EDT
• Current:Sky Time
• EDT:Add One Hour to EST
3. What's the importance of Aristarchus?
Measured the sizes and distances of the sun and moon fairly accurately, also proposed a sun centered universe
4. What's the importance of Ptolemy?
Mathematician who tried to make his bulky epicycle system work to explain the motions of the planets in the sky. He succeeded with a fair amount of accuracy.
5. What's the importance of Harrison?
Harrison is responsible for modern accurate timekeeping and made it possible for ships to accurately calculate their positions on the open sea.
6. Kepler's first law
The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus.
7. Kepler's second law
An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time.
8. Kepler's third law
The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun.
9. Define Zenith
a topocentric term referring to the point on the celestial sphere that is directly over your head, or straight up relative to local gravity.
10. Define Meridian
a topocentric term that refers to an imaginary line on the celestial sphere that runs from the North Celestial Pole through the zenith and continues to the South Celestial Pole.
11. Define Solar Day
the time from one transit of Sun until the next transit of the Sun
12. Define Mean Solar Day
the length of the Solar Day, averaged across the entire year.
13. Define Sidereal Day
the time from one transit of any particular star (or point on the celestial sphere) until the next transit of that same star
 Author: Anonymous ID: 283380 Card Set: Astronomy Unit One Part I Updated: 2014-09-18 00:18:10 Tags: Astronomy 1020 Folders: Description: Bosse Show Answers: