On 13 August your 0345 ZT DR position is LAT 21°35.0'N, LONG 135°26.0'W. You are on course 052°T at a speed of 14 knots. What will be the zone time of sunrise at your vessel?
• Zone description (ZD) and how to determine it from longitude • Using the Nautical Almanac sunrise tables for a given date and DR position • Applying longitude and time corrections (meridian passage / arc to time) to convert from GMT/UT to local zone time
• From 135°26.0'W, what is the correct time zone (ZD) you should apply, and is it plus or minus? • How do you obtain the approximate GMT/UT of sunrise for 13 August at about 21°N, 135°W from the almanac tables before applying the zone correction? • Once you have the UT of sunrise, what exact steps do you take to convert it to zone time, and how do you handle any date changes when applying the ZD?
• Confirm the correct sign and integer value of ZD for longitude 135°26.0'W • Make sure you are using the correct date (13 August) when entering the almanac tables and not accidentally using the next or previous day after applying ZD • Verify your final time is in zone time (ZT), not in GMT/UT, and that it is reasonably close to local 0600 for a tropical latitude sunrise.
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