On 19 July your 1500 ZT DR position is LAT 28°25.0'N, LONG 120°28.0'W. You are on course 233°T at a speed of 10 knots. What will be the zone time of sunset at your vessel?
• DR (Dead Reckoning) position and how to advance it using course and speed • Using the Nautical Almanac sunset tables for a given latitude and date • Converting GMT (UT) of sunset to zone time (ZT) using your longitude
• First, from 1500 ZT to around sunset, how long will you be steaming on course 233°T at 10 knots, and where will that put your DR position? • Once you know the DR latitude and longitude near sunset, what page/column in the Nautical Almanac tables will you use for sunset at that latitude on 19 July? • After you obtain the time of sunset in GMT (UT), what is your time zone description based on your longitude, and how do you apply it to get ZT?
• Be sure you use the DR position at the time of sunset, not the 1500 ZT position, when entering the sunset tables • Check that you’re using the correct date and latitude band in the Nautical Almanac (Northern vs Southern hemisphere, July 19, correct whole-degree latitude) • Confirm your zone description (ZD) sign from your longitude before converting UT to ZT so you don’t shift the time the wrong way
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