Tag Archives: astronomy

Astro Navigation In A Nutshell Part 2.

Part 2 – The Intercept Method Link:  Astro Navigation In A Nutshell Part One Astro Navigation in a Nutshell Part 3 Astro Navigation in a Nutshell Part 4 Suppose we are in a yacht and we measure the altitude of … 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 Astro Navigation in a Nutshell Part 3 Astro Navigation in a Nutshell … 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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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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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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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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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 Demystified Astro Navigation Course Unit 6

UNIT 6 –  Calculating zenith distance and azimuth at assumed position. We can use sight reduction tables to calculate the zenith distance and azimuth at the assumed position or else we can use the traditional method of making the calculations … Continue reading

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The Demystified Astro Navigation Course – Unit 4

Unit 4 – The Importance of Altitude, Azimuth and Zenith Distance in Astro Navigation.  Zenith. The Zenith is an imaginary point on the celestial sphere directly above the observer.  It is the point where a straight line drawn from the … Continue reading

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The Demystified Astro Navigation Course Unit 3 Part 2

Unit 3 Part 2 – Altitude Correction tables for the Sun, Stars and Planets. As shown in the table extract below, corrections for the Sun are divided into two parts to allow for changes in the Sun’s semi-diameter during the … Continue reading

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