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