At 1400 zone time on 11 April, your DR...

Question 1 of 2707066636eea28f7522a1c51aac7

At 1400 zone time on 11 April, your DR position is LAT 25° 40' N, LONG 91° 00' W. You are steering 180° T at a speed of 10.0 knots. What is your zone time of sunset?

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Question 1 of 27070

At 1400 zone time on 11 April, your DR position is LAT 25° 40' N, LONG 91° 00' W. You are steering 180° T at a speed of 10.0 knots. What is your zone time of sunset?

🔍 Key Concepts

• Use the Nautical Almanac daily pages for 11 April to find the Sun’s GHA and declination at the nearest whole hour in GMT/UT, then interpolate for minutes and seconds if needed • Convert your zone time (ZT) and assumed zone description (ZD) to Greenwich Mean Time (GMT/UT) before entering the Almanac • Apply the sunrise/sunset calculation method: estimate Local Hour Angle (LHA) at sunset using latitude, declination, and a tabulated or formula-based value for the Sun’s altitude at the visible horizon

💭 Think About

• What steps do you take to turn a zone time at DR position into the corresponding GMT so that you can work with the Almanac values? Think about your longitude and the proper sign of the zone description (ZD) • How does your latitude (25° 40' N) and the Sun’s declination on 11 April affect the hour angle at which sunset occurs? Is the Sun north or south of the equator on that date? • Once you find the time of sunset in GMT, how do you convert that back into local zone time at your longitude? Pay close attention to whether you should add or subtract your ZD

✅ Before You Answer

• Double-check your zone description (ZD) for LONG 91° W and make sure the sign is correct before converting between ZT and GMT • Confirm from the Almanac that you’re using the correct date (11 April) and not accidentally using the preceding or following day’s data • After you compute your sunset time, verify that your elapsed time from 1400 ZT to sunset makes sense for an afternoon sun at that latitude (i.e., does the interval seem too short or too long for a mid-April day in the low latitudes?)