On 22 November your 1400 ZT DR position is LAT 22°16.0'N, LONG 136°37.0'E. You are on course 038°T at a speed of 22 knots. What will be the zone time of sunset at your vessel?
• Zone Time (ZT) vs Greenwich Mean Time (GMT/UT) and how to convert between them using longitude • How to determine Local Mean Time (LMT) of sunset for a given latitude and date from the Nautical Almanac, then convert to ZT • How to compute time of travel from DR position time to the sunset meridian if any longitude correction is needed
• From longitude 136°37.0'E, what is your time zone description (ZD) and how do you get from ZT to GMT and back? • For 22 November and latitude 22°16.0'N, what is the printed sunset time in the Nautical Almanac, and is it given in GMT or LMT? • After you find sunset time at your position, do you need to adjust for any difference in longitude between your DR meridian and the standard time meridian for your zone?
• Verify your zone description (ZD) sign and size from the longitude (E vs W and nearest whole 15°) before doing any time conversions • Confirm whether the sunset time taken from the Almanac is given for LMT at the ship’s meridian or for a standard meridian, and adjust correctly • Re-check your time arithmetic, especially adding/subtracting hours and minutes, so your final ZT lines up with one of the choices closely
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