On 16 March your 0330 ZT DR position is LAT 22° 36.0' S, LONG 76° 16.0' E. You are on course 098° T at a speed of 16 knots. What will be the ZT of sunrise at your vessel?
• Nautical Almanac sunrise tables for 16 March at 22° S latitude • Conversion between GMT/UT and Zone Time (ZT) using longitude and time zone • Effect of ship’s movement (course and speed) on DR longitude at the time of sunrise
• First, at 22° S, find the nearest tabulated latitude in the Almanac and note the sunrise GMT for 16 March at that latitude and standard meridian longitude • Determine the appropriate time zone for 76° 16.0' E and work out the conversion between GMT and ZT for your vessel’s area • Account for how far the ship moves (especially in longitude) between 0330 ZT and the computed sunrise time, and decide whether you need to iterate your time estimate
• Be sure you are using Greenwich Date (G) correctly if your conversion crosses 0000Z • Confirm the correct zone description (ZD) sign based on being east of Greenwich • Check that your final sunrise time is expressed in Zone Time at the vessel, not GMT/UT
No comments yet
Be the first to share your thoughts!