On 16 February your 0300 ZT DR position is LAT 28°32.0'S, LONG 176°49.0'E. You are on course 082°T at a speed of 21 knots. What will be the zone time of sunrise at your vessel?
• DR (Dead Reckoning) position and how to advance it using course and speed • How to use the Nautical Almanac sunrise tables for a given date and latitude • How to convert between GMT/UT, zone time, and longitude using the zone description
• From 0300 ZT, how far (in time and distance) will the vessel travel before the approximate time of sunrise at that latitude in February? • How do you find the time of sunrise in GMT/UT at the ship’s DR position, then apply the correct zone description based on longitude? • After advancing your DR to the time of sunrise, is the latitude still close enough that the Almanac’s value is valid, or do you need only the initial DR position?
• Compute the zone description (ZD) from the longitude and check that its sign is correct for east longitude. • Confirm that you are using 16 February data in the Nautical Almanac and the correct latitude band (28°–29° S). • After converting sunrise time from GMT/UT to ZT, double‑check the arithmetic: addition vs. subtraction and handling of hour wrap‑around.
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