Navigation Unit 1-Planet Earth
What is Navigation? The science of locating a position on earth
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
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
GMT Greenwich Mean time (GMT) Time on the prime meridian (0°) in Greenwich England
Local clock Time Time where you are
Traveling and Time West of the prime meridian is earlier East is later We El 0°
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
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
Celestial Navigation Uses the stars (North Star) and the Sun to determine one ’ s location
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!!!
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°