Principles of Celestial Navigation
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Table of Contents
Introduction
Lesson Objectives
Basics
Linking the Spheres
Earth Position: Latitude and Longitude
Exercise
Celestial Position
Exercise
Geographic Position
Exercises
Using the Celestial Sphere for Geo-location
Degrees, Minutes, and Miles
Exercise
Circles of Position
Lines of Position
Exercises
The Sextant as a Tool
Measuring Angles and Altitude
Exercise
Using the Sextant
Exercises
The Intercept Method
Basics: Recap
Meet the Chief Quartermaster
Intercept Method Overview
Exercise
Observed Altitude (Ho)
Sight Reduction Process
Exercise
Assumed Position (AP) and Dead Reckoning Position (DR)
Setting Up the Plotting Sheet
Computed Altitude and Azimuth (Hc and Zn)
Determining Hc and Zn by Hand
Plotting
Exercises
A Day in the Life of a Navigator
Recap
Overview of a Day in the Life of a Navy Navigator
Dead Reckoning Plot
Preparing for a Morning Observation
Three-Star Fix, Morning
Exercise: Sight Reduction for Deneb and Fomalhaut
Deneb Sight Reduction
Fomalhaut Sight Reduction
Plotting the Morning Three-Star Fix
Morning Sun Line
Sight Reduction for Morning Sun Line
Exercise
Plotting the Morning Sun Line
Local Apparent Noon
Observing LAN
Exercise
Plotting the LAN Line of Position
Advancing a LOP
Estimated Position
Afternoon Sun Line
Obtaining a Running Fix
Preparing for the Evening Observations
Three-Star Fix, Evening
Exercises
Plotting the Evening Three-Star Fix
Summary
Supplemental Material
Determining Hc and Zn Using the Publications
The Nautical Almanac and Pub 229
Interpolation is Required to Use The Nautical Almanac
Selection of the “Assumed Position" is Important when Using Pub 229
Parallel Light Rays
References and Resources
Contributors
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The Intercept Method » Observed Altitude (Ho) »
Exercise
Let’s review. Select the appropriate label for each definition below:
The correction due to our eye not being at sea level:
-select an answer-
Altitude correction
Observed altitude
Sextant altitude
Dip correction
Dip correction
The height measured by a sextant:
-select an answer-
Altitude correction
Observed altitude
Sextant altitude
Dip correction
Sextant altitude
The correction accounting for Earth’s atmosphere causing light rays to bend:
-select an answer-
Altitude correction
Observed altitude
Sextant altitude
Dip correction
Altitude correction
The altitude of the celestial object, corrected for dip, atmosphere, and index errors:
-select an answer-
Altitude correction
Observed altitude
Sextant altitude
Dip correction
Observed altitude
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