Calculating Sunrise, Sunset, Star Time

Flashing Light
Watch Training Workbook
Campus Life
The Joe Show
Deck Skills
Celestial Nav.
Ship Structure
Rules of the Road
Ship and Cargo Ops.
Shipping Info
Shanties and Sea Lore
World Port/Drink Guide

Because The Sun Doesn't Come Out At Night

This is simple, useful, and you'll have to find these values on watches, so get it down and get it right.

Step 1: Find Value of Celestial Phenomena in Daily Pages of NA
Step 2: Interpolate for DLo.
Interpolate for the difference between your Longitude and the Longitude of Central Meridian of your time zone. If you assume the value from Daily Pages to be in LMT, adjust for your distance from Cent Mer. If assuming value to be GMT, correct for entire value of Longitude.
   - From your DR position at the time from the Daily Pages, the time of Meridian Passage you found is in LMT. To find ZT, find your DLo (the distance between you and the central meridian of time zone), and convert that to time either using your calculator or the arc to time conversion table on the first yellow page in the back of the NA.
   -If you are west of your central meridian, add your DLo minutes to time of Meridian Passage. If you are east of your central meridian, subtract your DLo minutes to time of Meridian Passage.
Step 3: Interpolate for Latitude using tables.
Do this with tables found just behind the Increments and Corrections pages in the yellow section of your NA.

That's it. You can use this method for Sunrise, Sunset, and either twilight. Moonrise is a little different and is described elsewhere.

Initial Value
0630 (LMT)
Long. Correction
Cent. Mer: 3000'W
You: 3100'W
DLo: 30-31 = 1(W) = 4m (W)
Apply Corr: 0630 + 4(W) = 0634
Lat Correction
Correction found in Tables in back of NA, (page xxxii). Entering values are the Tabular Interval and the Diff. between times for consecutive Lats. Tabular Interval is the difference between consecutive values of LAT in Daily pages. ex. The value after N10 is N20, but the value after N56 is N58. The difference between times for consecutive intervals should be self-explanitory, but to clarify, look at your nearest value in the Daily Pages, then look at the next nearest value. The difference between the values that bracket your latitude is the entering value here.
Final Value
Sum of Initial Value and Corrections