Category Archives: navigation

Astro Navigation In A Nutshell Part Four

Part 4 – Full procedure for establishing an astronomical position line. This post brings together all of the information from parts 1, 2 and 3 of this series to demonstrate the full procedure for establishing an astronomical position line. .Links:  Astro … Continue reading

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Astro Navigation in a Nutshell Part 3

Part 3 – Calculating Altitude and Azimuth at the Assumed Position by Spherical Trigonometry. Links:  Astro Navigation In A Nutshell Part One Astro Navigation In A Nutshell Part Two There are several ways of calculating the azimuth and altitude at the … Continue reading

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Applying the Equation of Time when calculating longitude at the Sun’s Meridian Passage.

Author’s Note:  The original issue of this post was found to contain errors which have now been corrected.  Many thanks to Jeremy Parker for bringing the errors to my attention. Although the imaginary Mean Time gives us an accurate measurement … Continue reading

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Short Distance Sailing And Rhumb Line Sailing

In my previous post about the meridian passage long method, I demonstrated how the ‘Short Distance Sailing Formulas’ are used to calculate a vessel’s position at meridian passage.  I have since received several questions asking how these formulas allow for … Continue reading

Posted in astro navigation, Astro Navigation Demystified, Astro Navigation Topics, celestial navigation, geometry, Marine Navigation, mathematics, navigation, Schools, spherical trigonometry, Topics For Schools, trigonometry | Tagged , , , , ,

Meridian Passage Long Method

Links:  Understanding Meridian Passage, Equation of Time,   Meridian Passage Short Method,  Short Distance Sailing Formulae,  What is the point of meridian passage?         Zone Time,    Local Hour Angle and Greenwich Hour Angle,   Converting GMT to GHA … Continue reading

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Understanding Meridian Passage (Mer Pas)

Meridian Passage occurs when a celestial body crosses the observer’s meridian of longitude and at that instant, it will reach its greatest altitude above the observer’s horizon. The following diagrams will help to explain how the latitude can be calculated from the … Continue reading

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The Tidal Effects of the Moon

Continuing the series on the moon. If it were not for the gravitational attraction of the Sun and the Moon, the water level of the seas and oceans would be kept at equal levels by a combination of the Earth’s … Continue reading

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The Moon

My recent article ‘Finding Direction By The Moon’, sparked off a flurry of correspondence on the topic of the usefulness of this celestial body in navigation and in response, the next few articles will be on this subject. PHASES OF … Continue reading

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Survival – Finding Direction From The Moon.

Just as the Sun can help us to find our general bearings during the day, so can the Moon at night. Moonrise and Moonset.  As in the case of the Sun, the Moon will rise between north east and south … 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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