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6. Determine the difference between your DR latitude and the tabulated latitude nearest yours. Convert the difference into degrees to the nearest whole degree.
DR LAT 23S
TAB LAT 20S
DIFF. 3 Degrees
7. Determine the latitude time correction by multiplying the difference by the ratio in step 6 and rounding it to the nearest minute.
1.4 min x 3 degrees = 4.2 or 4 min
1.1 min x 3 degrees = 3.3 or 3 min
8. Apply the latitude correction to the tabulated latitude time value. This is the time of moonrise at the standard meridian at that latitude if the Nautical Almanac tabulated twilight for every whole degree of latitude.
20S 0058 - 0018
- 4m - 3m
23S 0054 - 0015
9. Find the time difference between the dates.
30th 0054
29th 0015
diff 39 min
10. Now enter Table II for Longitude - {Tables for Interpolating Sunrise Moonrise, Etc. } page xxxii at the back ·of the Nautical Almanac for the longitude correction. Enter with your DR Long approx. 160° E and difference of 39 minutes and you get a correction of 18 minutes. This time is subtracted for east Long and added if in west Long.
0054
-18
0036
11. Determine the difference between your DR lonitude and the standard meridian.
STD MER. 165-00.0E
DR LONG 159-46.3E
DIFF. 5-13.7
5 Degrees = 20 min
13.7 = 0m 55s =21min
12. Convert the arc ( degrees and minutes ) into time ( hours and minutes ). Use either the arc to time table in the Nautical Almanac or the arc to time formulas.
13. Apply the difference of the time to obtain the exact time of moonrise.
MR at STD MER 0036
+ 21
ZT of MOONRISE 0057
