1. Navigation Unit 1-Planet Earth

2. What is Navigation?  The science of locating a position on earth

3. What is navigation based upon?  A coordinate system or grid system of imaginary lines on earth ’ s surface  Theses lines coincide with the time of day and the position of the North Star or Polaris in the Northern hemisphere

4. Time:  Day-Based on motions of earth (rotation)  24h to rotate/ 360°  15°/hr  Month-Based on motions of the moon around the earth  Year-Based on motions on the Earth around the sun

5. GMT  Greenwich Mean time (GMT)  Time on the prime meridian (0°) in Greenwich England

6. Local clock Time  Time where you are

7. Traveling and Time  West of the prime meridian is earlier  East is later We El 0°

8. Terrestrial Coordinate Systems: Latitude  Latitude: a measure of the angular distance North or South of the Equator  Measures 0-90°  Lines are horizontal or run parallel to the equator thus called parallels  Never meet

9. Terrestrial Coordinate Systems: Longitude  Longitude: lines that measure the angular distance east or west of the prime meridian  Measures 0-180°  Also called meridians  Are vertical  Meet at the poles

11. Celestial Navigation  Uses the stars (North Star) and the Sun to determine one ’ s location

13. To Find Latitude:  If you know the altitude of the North Star or Polaris you can find your latitude  THE ALTITUDE OF POLARIS IS EQUAL TO THE LATITUDE OF THE OBSERVER!!!

14. To Find Longitude:  Must know your local time and the time on the prime meridian; and if you are east or west of prime meridian  Determine time difference  Multiply difference by 15°