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Astro Navigation In A Nutshell Part 1

Part 1 – The Importance of Azimuth and Altitude.  The theory of astro navigation depends on the ability to solve the spherical triangle PZX in the diagram below.  The azimuth and altitude enable us to calculate the Local Hour Angle … Continue reading

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Meridian Passage Short Method

Meridian Passage Methods.  Short Method.  In the case of stationary or very slow moving vessels, it is acceptable to use the Meridian Passage Short Method which involves calculating the time of meridian passage at the current DR position. Long Method.  … Continue reading

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Altitude Corrections For The Moon

Continuing the series on the Moon. When a navigator measures the altitude of the Moon, there are several corrections that he has to make to the readings. Corrections For The Moon’s Semi-Diameter.  The point on the Moon’s circumference nearest to … Continue reading

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Survival – The Daytime Star

Just as the stars can be your compass at night, there is another star to guide you during the day and that of course is the Sun. Sunrise/Sunset.   We are taught that the Sun rises in the East and sets … Continue reading

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The Astro Navigation Resource

See the latest post:   The Celestial Co-Ordinate System Although this website aims to promote the Astro Navigation Demystified series of books, it is hoped that it will also provide a useful resource for navigators, scholars and students of the subject. A wealth … Continue reading

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The Demystified Astro Navigation Course – Unit 5

Unit 5 – Demonstration of a 3 point fix. Aim.  We saw in unit 4 how a position line is obtained from a single intercept; the aim of this demonstration is to establish a 3 point fix based on the … Continue reading

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The Role Of Altitude, Azimuth And Zenith Distance In Astro Navigation.

Point Z represents the zenith of the observer’s position.  Point X represents the position of the celestial body and this point, if projected onto the Earth’s surface, would correspond to the Geographical position of the body. P and P1 are … Continue reading

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First Point of Aries.

First Point of Aries.  In astronomy, we need a celestial coordinate system for fixing the positions of all celestial bodies in the celestial sphere.  To this end, we express a celestial body’s position in the celestial sphere in relation to … Continue reading

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The Accuracy of Astro / Celestial Navigation

 U.S. Navy and Royal Navy navigators are taught that the accuracy of astro navigation is ±1 minute of arc or 1 nautical mile and that where position lines are derived from astronomical observations, the resultant position is not known as a … Continue reading

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Finding Stars and Constellations – Part III

This post continues the series Finding Stars and Constellations. Lyra, Cygnus and Aquila – The Summer Triangle. The diagram below shows the constellations Lyra, Cygnus and Aquila. If we follow the reference line ‘the Pointers’ from Ursa Major to Polaris, … Continue reading

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