Author Archives: Jack Case

Revise Pythagoras’ Theorem

Posted on January 8, 2012 by Jack Case

If after reading some of my other posts, you feel you are a bit rusty on Pythagoras’ Theorem, here is a quick brush up for you.  We can see in the diagram below that, in the triangle ABC, if a … Continue reading →

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Declination Table For Survival Use

Posted on January 8, 2012 by Jack Case

Sun’s Declination Table constructed for use in survival situations to be used when calculating latitude from the altitude of the midday sun. Provided by Astro Navigation Demystified (www.astronavigationdemystified.com) The following table shows the mean values of the declination of the … Continue reading →

Posted in Astro Navigation Topics, Survival | Tagged , , , , , | 2 Comments

How To Make A Mini-Clinometer For Survival Use

Posted on January 8, 2012 by Jack Case

A clinometer is a simple device that can be used to measure the altitude of an object. Despite its simplicity, a clinometer provides a level of accuracy sufficient to measure angles to the nearest degree.  A ‘mini-clinometer’ as shown below, … Continue reading →

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Could the Global Positioning System Fail?

Posted on January 8, 2012 by Jack Case

Quite apart from the local risks of defective equipment, battery failure, generator failure and short-circuits to electronic navigation equipment caused by flooding, there is a very real global risk that the GPS could be destroyed. During periods of increased solar … Continue reading →

Posted in Astro Navigation Topics | Tagged , , , , , | 4 Comments

Latitude from the Midday Sun

Posted on January 8, 2011 by Jack Case

Finding Your Latititude From The Midday Sun. The following diagrams will help to explain how the latitude can be calculated from the Sun’s midday altitude and its declination.  In the following diagram , NOS  represents the horizon and O represents … Continue reading →

Posted in Astro Navigation Topics, Schools | Tagged , , , | 2 Comments