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Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
Celestial navigation
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Celestial navigation

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  • What would you do without all these things?
  • Step 1 – figure out what hemisphere you’re inPlenty of ocean to get lost in
  • Celestial pole – lucky if you’re in the north, polaris is at the poleLearn your landmarks – the two bears in the north, the southern cross in the southFind the southern pole by drawing a line from acrux and the tip of the cross and between agena and rigelcentaurus, lines intersect at the southern celestial pole
  • 20 billionths of an inch4 billion miles
  • Transcript

    • 1. Sailing by Starlight: the Lost Art of Celestial Navigation
      Andrew Thaler
    • 2. Do you know where you are?
    • 3. Finding your way home
    • 4. Finding your way home
      Southern Sky
      Northern Sky
    • 5. Finding your way home
      How do you travel in a straight line?
      Latitude hook
      Must be calibrated to a specific location
      Polaris above the loop, head south
      Polaris below the loop, head north
      Kamal
      Why does this work?
    • 6. Determining Latitude
      Polaris
      tan θ = x/y
      θ = Latitude
      X
      θ
      Horizon
      y
    • 7. Determining Latitude
      Accurate to within 1 Degree
      1 degree of latitude = 60 minutes
      1 minute = 1 nautical mile
      Polaris is 430 light years away
      2.5 X 1015 miles
      If surveyors were as accurate as Polaris - 0.0000000002 inches
      If Polaris was as accurate as a surveyors - 4,000,000,000 miles
    • 8. Latitude is θ
      Cross staff
      Quadrant
      Astrolabe
      Octant
      Sextant
    • 9. Longitude
      The X-Prize of the millennium
      No accurate method until 19th
      century
      3 puzzle pieces
      Rotation of the earth = 15o per hour
      Time the sun peaks at prime meridian = 1200
      Time (GMT) the sun peaks at your location
    • 10. Relative Longitude
      Not very accurate!
      Find a star near the eastern or western horizon
      Measure the altitude of that star at the same time every night
      Changes in degrees correspond to movement east or west
      2 Caveats
      Need to correct for latitude
      Need to know what time it is
    • 11. What time is it?
      The sky is a clock, too
      Mariner’s Nocturnal
      Measures the angle between Polaris and Ursa Major or Ursa Minor
    • 12. Using the Nocturnal
      • An analog computer
      • 13. Set the dial to the date
      • 14. Sight Polaris through the center hole
      • 15. Rotate the arm until it lines up with the head of Ursa Major
    • Astronomers and Mariners
      None of these tools were invented for navigating
      We know where we are on earth because we wanted to know where we are in the universe
    • 16. Questions?

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