Category Archives: Marine Navigation

Planning Star and Planet Sights

Fixes from Sightings of Stars and Planets.  There are 59 navigational stars and 4 navigational planets which we can use to achieve position fixes. However, there are only two short periods during the day in which we can do this … 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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Stars For All Seasons Part 7 – Spring Stars in the Northern Hemisphere.

Spring Stars in the Northern Hemisphere. Spring is just around the corner and when the winter constellations begin to make their exits to the west, we will find Boötes, Leo, Cancer, Hydra and Virgo lurking in the wings ready to … Continue reading

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Stars For All Seasons Part 6

Winter Stars in the Northern Hemisphere “Know The Stars And You Will Always Have A Compass”.    (Michael Punk. 2002. The Revenant)   As we move into winter, new constellations take their place in the night sky of the northern hemisphere … 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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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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Bearing, Azimuth and Azimuth Angle.

For students of astro navigation, the various definitions of azimuth, azimuth angle and bearing can cause much confusion. It is hoped that the following will help to clarify this topic. Bearing is the direction of something in relation to a … Continue reading

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Astro Navigation In A Nutshell Part Four

Part 4 – Full procedure for establishing an astronomical position line. This post brings together all of the information from parts 1, 2 and 3 of this series to demonstrate the full procedure for establishing an astronomical position line. .Links:  Astro … Continue reading

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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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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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