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Noon and navigation

Traditionally ships kept their clocks in time with the local time zone for two purposes. Firstly to be on the correct time for entering port, harbour etc.. Secondly it was to enable the sun to be overhead around “Noon” for the Navigator to fix the ship’s position.

Traditionally ships kept their clocks in time with the local time zone for two purposes. Firstly to be on the correct time for entering port, harbour etc.. Secondly it was to enable the sun to be overhead around “Noon” for the Navigator to fix the ship’s position. During an ocean passage ship’s clocks would be adjusted (in 30 or 60 minute segments) forwards or backwards to keep the sun overhead (noon) between 11:30am and 12:30pm. The noon sextant sight was important as it provided the navigator with the latitude of the ship. Sun sights, taken through the morning, would be plotted to determine the correct longitude. The noon position would then be used to calculate the course and distance steamed since the previous noon “fix” (or departure point) and the course, distance and Estimated Time of Arrival (ETA) at the destination. Star sights would be taken at twilight (morning and evening) to confirm that the ship was on course to its destination.

Then GPS and satellite navigation came along and this information is now readily available to us at any time of the day and night. It is good to see, however, that the traditional art of celestial navigation is alive and well on Europa.

Howard

Written by:
Howard | Trainee

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