CELESTIAL NAVIGATION & Sextant Instruction
for the Sun Noonshot
Two complete 1-hr. lectures: #1 on theory and the Nautical Almanac;
#2 on Sextant Use and a complete Sun Noonshot.
Free Downloadable Noonshot Worksheet available.

Item #303.........120 minutes

 
Celestial Navigation - The NoonshotTwo complete 1-hr. lectures: Gene Grossman (Magic Lamp's Skipper) does lecture #1 on theory and the how to use the Nautical Almanac. Paul Miller (former U.S. Naval Academy Instructor) does lecture #2 on how to use a Sextant and then shows the complete taking of a Sun Noonshot, filling in each line of the worksheet for you. Free Worksheet included.

Originally sold for $49.95, but now available for only $34.95. The knowledge you will get from this DVD on the Sun NoonShot, combined with the information in our 2-hour DVD #203 "Basic Celestial Navigation w/Stars, Moon & Planets" will give you the skills you need to sail around the world with only a sextant to determine your position, day or night.

 
Complete DVD Table of Contents  -  CLICK HERE TO DOWNLOAD YOUR WORKSHEET
 
I. INTRODUCTION: 2 JERKS IN A POWERBOAT GETTING LOST

II. 10-min. REVIEW OF COASTAL PILOTING (In Sight Of Land)

A. Direction & Distance from a known point

1. Landmarks (on land)
2. Celestial bodies

B. History of the Compass (in Magnesia, centuries ago)
C. The Compass Card: 360 degrees around (& the lubber line)
D. Within Sight Of Land:

1. Relative and Reciprocal Bearings
2. Triangulation between 2 landmarks (2-Bearing Fix)
3. Using Dividers to locate Lat. & Long. of fix
4. Using the Nautical Mile scale on the chart
5. Difference between Nautical Mile and Statute Mile [Each Nautical Mile=One Minute (1/60th) of a Degree]

III. LECTURE 1.: INTRODUCTION TO CELESTIAL NAVIGATION

A. The GP (Geographical Position, or "Ground Point")
B. the Equator and the Greenwich Meridian
C. Parallels of Latitude (0 to 90 degrees North or South)
D. Meridians of Longitude (0 to 180 degrees E or 180 W)
E. Declination (same measurement as Latitude)
F. Greenwich Hour Angle (GHA) (0 to 360 degrees around)

IV. THE NAUTICAL ALMANAC: GP of all Navigational Celestial Bodies for each second of time

V. DETERMINING BOAT'S DISTANCE FROM A CELESTIAL BODY's GP

Boat's Zenith: line straight up from center of earth through the boat

VI. WHAT THE SEXTANT MEASURES (it's all done with mirrors)

A. Using the Horizon to Determine reciprocal Zenith Distance (from boat's perpendicular to the celestial body)
B. Bringing the celestial body down to earth
C. Reading a Sextant's vernier scale (some examples shown)

VII. SEXTANT CORRECTIONS ON THE WORKSHEET

A. INDEX Correction (IC): errors ON the arc and OFF the arc
B. DIP: height of eye above sea level at time of sighting
C. LIMB: for Sunshots - upper limb or lower limb being shot
D. REFRACTION CORRECTION: accounts for bent light rays
E. PARALLAX CORRECTION (used mainly for Moonshoots)

VIII. TIME: Corrections on the Worksheet for Greenwich Mean Time

A. Elimination of the Worksheet's Time Corrections

1.maintain accurate quartz watch set to GMT 24-hr. time
2.WWV radio signals for daily settings to UTC time-beeps
3.universal time coordinated (UTC)

B. Sunspeed: 15 degrees(900 nautical miles) per hour
C. Marking the Time of the Sextant shot

IX. DEFINITION OF THE MERIDIAN CROSSING

A."High NOON"
B.Shot to determine Latitude & Longitude at Local Apparent Noon (LAN)

X. THE NAVIGATIONAL TRIANGLE: how it is solved by the tables

-----------END OF FIRST HOUR-----------

XI. SECOND LECTURE: PAUL MILLER, former USNA instructor "LATITUDE & LONGITUDE AT NOON: THE NOONSHOT" [Noonshot Worksheet is proved to all video purchasers]

A. TAKING A NOONSHOT and filling in the Worksheet
B. WATCH TIME LAN portion of the Worksheet

LINE 1: Date of shot being taken
LINE 2: entering the NOON DR Latitude
LINE 3: NOON DR Longitude (Great Circle, defined)
LINE 4: The Time ZONE CENTER: GMT
LINE 5: DISTANCE FROM ZONE CENTER
LINE 6: Using Nautical Almanac: time of Meridian Pass.
LINE 7: Time to MERIDIAN PASSAGE from Zone time NOON
LINE 8: LOCAL WATCH TIME OF GMT LAN C. Time Notations for DECLINATION Section of Worksheet
LINE 9: Declination Time
LINE 10: Time Zone Description
LINE 11: Insertion of GMT of Meridian Passage
LINE 12: Declination at GMT of Meridian Passage

XII. USING THE SEXTANT TO TAKE A NOONSHOT

A. How to USE the Sextant: parts of sextant displayed
B. How to READ the Sextant: vernier, micrometer drum
C. Sextant Corrections on the Noonshot Worksheet

LINE 13: "hs" Raw sextant reading (sextant height)
LINE 14: Index Correction: zeroing out the mirrors
LINE 15: "dip" Correction: height of eye above seawater
LINE 16: Apparent Altitude: corrected for Index & Dip
LINE 17: Limb correction (for portion of body sighted)
LINE 18: other corrections (parallax, refraction, temp.)
LINE 19: "HO" totally corrected sextant reading of alt.

XIII. ZENITH DISTANCE (defined and illustrated)

LINE 20: standard amount pre-filled in on worksheet
LINE 21: subtraction of HO from Line 19
LINE 22: Zenith Distance determined

XIV. LATITUDE CASES 1 & 2 (depending on location re geography)

A. Cases 1 & 2

LINE 23: Declination (greater or less than DR latitude)
LINE 24: Figuring in the Zenith Distance
LINE 25: Actual LATITUDE figured out

B: Case 3 (if geography dictates)

LINES 26, 27, 28

XV. LONGITUDE

LINE 29: Averaging of times to calculate LAN crossing
LINE 30: Taking ZONE DESCRIPTION (from GMT) into account
LINE 31: Exact GMT of LAN (Meridian Crossing time)
LINE 32: Finding GMT GHA (longitude) of sun at crossing
LINE 33: Nautical Almanac data entry for time interpol.
LINE 34: Corrected entry for Longitude of LAN crossing
LINE 35: Final computation of LONGITUDE

XVI. THE PLOTTING SHEET Using Lat. & Long. information from LINES 25 & 35

XVII. FINALE (more tips on how to actually use the SEXTANT)

A. SEXTANT Adjusting to eliminate errors: using filters
B. Listening to the time beeps on a short-wave radio
C. The artificial Horizon (if real one not available)
D. "Rocking the Sextant" for a more accurate shot

Order This Celestial Navigation DVD ....... $34.95

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