c e l e s t i a l n a v i g a t i o n ship 609 sea explorers - bsa edward s. popko
TRANSCRIPT
Scorpius
LibraVirgo
Leo
Boötes
Hercules
SagittariusCapricorn
Aquarius
Pisces
Pegasus
Andromeda
Aries
Taurus
Orion
Canis Major
Cancer
Ursa Major
Ophiuchus
Cygnus
Gemini
AurigaPolaris
Deneb
Altair
Vega
Arcturus
Spica
Regulus
Procyon
Rigel
Capella
Cassiopeia
Sirius
Castor
Pollux
Aldebaren
Antares
C e l e s t i a l N a v i g a t i o n
Ship 609 Sea Explorers - BSA
Edward S. Popko
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
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
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
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
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
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
Every Sight Results in one LOP on your Chart!
Look at the Sun, Moon, Planets & Stars
What Stars Tell UsEvery Celestial Body has a Ground Point - GP
Sextant AngleGP
GP
Nautical Almanac had GP for all times every day
Taking a Sight
What Time is it?
What Angle is it?
What Body are we Looking at?
1
2
3
Sextant Measures Angles - Nothing More!
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
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
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
You already have most of the stuff you need.
Demonstrations
A Two Day Boating Cruise
Finding The Camp Site at a State Park (Landlocked)
Fix from Two LOPs
C 075
C 075
S 12.5
S 12.5
1500 FIX
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
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
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
The End