Search Results for: Local hour angle

What are Local Hour Angle and Greenwich Hour Angle

Local Hour Angle (LHA). In astro navigation, we need to know the position of a celestial body relative to our own position. In the diagram below: LHA is the angle BNU on the Earth’s surface which corresponds to the angle ZPX … Continue reading

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Local Hour Angle and Greenwich Hour Angle

Local Hour Angle (LHA). In astro navigation, we need to know the position of a celestial body relative to our own position. In the diagram below: LHA is the angle BNU on the Earth’s surface which corresponds to the angle … Continue reading

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Local Hour Angle

Local Hour Angle (LHA).  In astro navigation, we need to know the position of a celestial body relative to our own position. In the diagram below, LHA is the angle BNU on the Earth’s surface which corresponds to the angle ZPX in … Continue reading

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Exercise 4 – Local Hour Angle.

This post continues the series of navigation related exercises which were requested by navigation course and nautical college teachers.  When the post expires, its contents will be included under the menu heading ‘Navigation Exercises’ on the home page. Local Hour … Continue reading

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Survival – Calculating Altitude Without An Angle Measuring Instrument

Links:  Astro Navigation in a survival situation.    Latitude from the midday Sun.    Find your longitude.     Calculating declination.    Declination table.     Trig table.    Revise trigonometry  Revise Spherical Trigonometry As the above links demonstrate, there are several methods of employing astro navigation … Continue reading

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Survival – Calculating altitude without an angle measuring instrument.

  Links:  Astro Navigation in a survival situation.  Latitude from the midday Sun.    Find your longitude.     Calculating declination.    Declination table.     Trig table.    Revise trigonometry. As the above links demonstrate, there are several methods of employing … Continue reading

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The Importance of Morning and Evening Star Sights – Part 2

The ‘Where To Look’ Method. Devised by Jack Case In part 1 of this series, we discussed how we can establish whether or not a selected star  or planet will be visible during nautical twilight.  In this post, we discuss … Continue reading

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The Importance of Morning and Evening Stars – Part 2

The ‘Where To Look’ Method. Devised by Jack Case As discussed in part 1, our aim in, astro navigation, is to calculate the azimuth angle and altitude of a celestial body from our DR position and then to compare the … Continue reading

The Importance Of Morning And Evening Star Sights

Part 1 – Checking to see which stars and planets will be above the observer’s horizon during Nautical Twilight. By Jack Case Introduction. The Astronomical Position Line.  A position line is a line drawn on a nautical chart along which … Continue reading

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THE IMPORTANCE OF MORNING AND EVENING STAR SIGHTS

Part 1 – Checking to see which stars and planets will be above the observer’s horizon during Nautical Twilight on a certain day. By Jack Case INTRODUCTION The Astronomical Position Line.  A position line is a line drawn on a … Continue reading