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C e l e s t i a l N a v i g a t i o n

History of Celestial. Oldest Form of Land / Sea / Air NavigationEarly Records Date to 1500BCUsed by Arabs for Desert CrossingsKamal and AstrolabeUsed in Oceania / Polynesia for 1000 YrsUsed in Gemini, Apollo, Shuttle ProgramsBackup on all Military Ships

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C e l e s t i a l N a v i g a t i o n

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    2. History of Celestial Oldest Form of Land / Sea / Air Navigation Early Records Date to 1500BC Used by Arabs for Desert Crossings Kamal and Astrolabe Used in Oceania / Polynesia for 1000 Yrs Used in Gemini, Apollo, Shuttle Programs Backup on all Military Ships & Aircraft Long Line of Incremental Improvements Sextant: Based on John Davis’s Backstaff 1590 Time: John Harrison’s Ocean Going Chronometer 1735 Math and Procedures: Nathaniel Bowditch 1838 LOPs: John Sumner 1875

    3. Why is Celestial Important? Essential to Survival at Sea Critical Backup to Electronic Navigation Insurance for “Lazy” Piloting and DR Work Very Useful in Coastal Navigation Distance Off 3 Point Fix Collision Avoidance Required in Some Sailing Events (Marion/Bermuda..) Pure Enjoyment Applied Astronomy Backpacking/Recreation Key to History of Ships, Commerce, Warfare, Discovery, Applied Astronomy

    4. What is Celestial Navigation Exploiting the Regular Motions of Stars and Planets to Determine Where You Are Every Sighting with a Sextant Results in a Line of Position (LOP) Lines of Position can be Plotted on a Chart You Are Somewhere on That Line! The Intersection of Two or More LOPs results in a fix

    5. What Do You Use if For? Locating Lines of Position, Establishing FIXs Checking your Speed & Course Determining Effects of Current and Wind on Boat Calibrating your Compass

    6. What Do You Use if For? Locating Lines of Position, Establishing FIXs Checking your Speed & Course Determining Effects of Current and Wind on Boat Calibrating your Compass Map Making Backpacking / Survival Distance-Off Collision Avoidance Basic Astronomy

    7. Basic Theory Every Celestial Body has a Ground Point - GP You Measure Angle of Body to Horizon Assume a Location “Reduce the Sight” Compare Computed and Assumed Location Plot Results

    8. What Stars Tell Us

    9. Taking a Sight

    10. Basic Procedure Identify Celestial Body Measure it’s Height above the Horizon (Sextant) Time Exact Moment of Sighting Use Nautical Almanac to find Ground Point of Body Assume a Position “Reduce the Sight” Plot Resulting LOP and Azimuth on Chart Update Dead Reckoning

    11. A “Celestial Day’s Work” Morning Twilight Stars for a Fix Mid-Morning Sun / Moon / Venus Noon Sun (for Latitude) Mid-Afternoon Sun / Moon / Venus Evening Twilight Stars for a Fix Special LOPs Coarse Speed Longitude Latitude (Local Noon) Course Plotting, DR Updates, FIX, Other

    12. What do You Need? Accurate Watch (You have one) Sextant (a $20 plastic sextant is fine) Large Lake or Ocean View or ..... Dish of Water or Old Motor Oil (All are Free) Makes Artificial Horizon Nautical Almanac (Must have - $5- get at boat stores) Small Area Plotting Sheet ( Draw your own chart) Drafting Items .. Pencils, Protractor (You have them) Optional Items (You have them) Calculator Star Guide from Astronomy Magazine or Newspaper

    13. Demonstrations A Two Day Boating Cruise Finding The Camp Site at a State Park (Landlocked)

    14. Fix from Two LOPs

    15. What Limits Celestial Must have Clear View of Horizon Limited Dawn and Dusk Star Fix Window Using Sextant from Small Pitching Boats Weather and Sky Visibility Dawn / Dusk / Daytime Only

    16. How Do You Learn it? Read Boy Scouts’ “Sea Exploring Manual” Try Astronomy Merit Badge Visit a Planetarium (Mystic Sea Port, Haydan...) Take an Off-Shore Navigation Cruise Ocean Star from Ocean Navigator Magazine Teach Yourself in the Back Yard Plastic Sextant + Artificial Horizon + Back Yard/Camping Site Take a Class U.S. Power Squadron. Coast Guard, Marinas etc. Attend a Boat Show Clinic Read Astronomy Magazines Visit a Maritime Museum

    17. What is New after 1500 Yrs.? Inexpensive Calculators that do all the Math High-Tech Sextants Composite Plastics Very High Quality Mirrors / Scope Optics / Filter Design Built-in Clocks and Sight Log Memories Artificial Horizons - Can Sight from Land or at Night Night Vision Telescopes - Can Sight all Night Automatic Azimuth/Compass Units Celestial & Star Calculators Links to PC Navigation and DR Plotting Applications in the Space Program Shuttle, Hubble, “Guide Star” Projects PC Simulators

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