Category Archives: celestial navigation

Stars For All Seasons Part 2 – Revolution

In the last article, we discussed rotation, the reason why stars rise earlier each night; in this article we discuss revolution, the reason why the stars in the night sky change from season to season.  In the diagram below we … Continue reading

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Stars For All Seasons Part 1

Often asked questions: Why do the stars seem to rise earlier each night?  Why do the stars that we see in the night sky change from season to season?  There are two separate reasons for these phenomena, Rotation and Revolution. … Continue reading

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Accuracy of Sight Reduction Methods.

In my recent article ‘Why Astro‘, I highlighted the risks in using the GPS.  Since writing that article, I am frequently asked “if astro / celestial navigation is to be used, which of the many systems is the best”.  Sight … Continue reading

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In Defence of Mer Pas

The noon sight for latitude is a method of calculating latitude from the altitude of the sun at the instant it crosses your meridian and for this reason, the method is also known as ‘Meridian Passage’ or ‘Mer. Pas’.  I … Continue reading

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Celestial Navigation – Theory and Practice

I have received a number of messages asking why my book ‘Celestial Navigation – The Ultimate Course’ is not currently available.  The truth is that I have been spending the winter months revising and updating this book and it will … Continue reading

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Why Astro?

In a recent article the discussion centred on our over-reliance on GPS for navigation at sea and the need for back-up systems.  The conclusion drawn was that we already have a back-up system, one that has been tried and tested … Continue reading

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Astro Navigation in the Forests of the Iroquois

Link: History of the Mason Dixon line Jeremiah Dixon and Charles Mason plotted the famous Mason Dixon Line in 1765, long before the days of GPS or any other electronic navigation equipment. How was it then that they were they able … Continue reading

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Translating A Celestial Position Into A Geographical Position.

This follows the previous post which discussed the Celestial Co-ordinate System. If we wish to use a celestial body’s position in the celestial sphere to help us to navigate on the Earth’s surface, we must be able to translate that … Continue reading

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The Celestial Co-ordinate system.

In astronomy, we need a celestial co-ordinate system for fixing the positions of the celestial bodies in the celestial sphere. We express a celestial body’s position in the celestial sphere in relation to its angular distance north or south of … Continue reading

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What’s The Point of Astro Navigation When We Have The GPS?

Imagine that you are driving through Birmingham when, suddenly, your ‘Sat Nav’ starts to tell you that you are in Manchester.  In such a situation, you would quickly realise that the GPS had gone haywire; however, if you were in … Continue reading

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