Andreww at 05:06, 4 February 2008

2008-02-04T05:06:41Z

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[[Navigation Contents |Contents]] | [[Navigation Glossary |Glossary]] | [[Navigation_to_other_Planets |<< Previous Chapter]] | [[Navigation Exercise 2| Next Chapter >>]] [[Category: Regiment for the Sea]] __NOTOC__

To work out your Latitude, you will need to know
* Days from Equinox (negative during Northern Winter)
:and one of:
* The Sun's Elevation at Noon
* Hours of Sunlight
* Bearing at Dawn

Calculate Seasonal Tilt, using either the [[Navigation and Seasonal Declination|Chapter Five]] charts, or the advanced [[Navigation Exercise 2#Seasonal_Declination| formulae]].

===Latitude from Elevation at Noon===
* Latitude = Seasonal Tilt + (90 - Sun Elevation at Noon)
''Note'' This method is covered in more detail in [[Navigation using Declination|Chapter Seven]]

===Latitude from Hours of Sunlight===
* Latitude = ArcTan( Sine((SunlightHours-12)*7.5) / Tan(SeasonalTilt) )
''Note'' This method is wildly sensitive to measurement errors during the middle months of Spring and Autumn, and is not great during the rest of these seasons.

===Latitude from Bearing at Dawn===
* Latitude = ArcCosine(-Sine(Seasonal Tilt)/Cosine(Bearing at Dawn))
''Note'' This method is wildly sensitive to measurement errors except near the Arctic circles in local Summer.

Navigation Exercise 1 - Revision history

Andreww at 05:06, 4 February 2008