[don1reed]

@Kv29: Closest I could get was a quick mission of 17 JAN 44 but from the same location: 21-14N 157-59W. My real life nav pgm for that date and year shows 18:02:40 for sunset, Azimuth 246° true.
The Sun tables of van shows 17:42
When the red light came on 17:08
34 minute difference is really not accurate enough to navigate by.

21° is 1/10 of the distance between the given angles in van's table.
There happens to be 21 minutes difference between the times for those angles. We can now interpolate:

1/10 x 21 = 2.1 min

We can subtract 2.1 min from 17:33 = 17:31 should be the time for sunset of our latitude IF the sun tables were accurate.

@ Mav:

Oahu is in Time Zone +10. This means we have to add 10 to obtain GMT.

Now, as we proceed westward, crossing the Date Line we gain a day (adding 24 hours to local time) GMT remains the same, but, to convert GMT to local time once we're west of the Date Line the sign is negative,


example: sailing west

ZT +10 local time 0100 date 3 JAN 44 = 1100 GMT
ZT +11 local time 0200 date 3 JAN 44 = 1300 GMT
ZT +12 local time 0300 date 3 JAN 44 = 1500 GMT
ZT -12 local time 0400 date 4 JAN 44 = 0400 GMT

The easiest way to do this if you use XCEL or some other spreadsheet is to build yourself a GMT conversion chart.

Left column top to bottom = local time 0000 to 2300.

Top row left to right Zone Times:
Y-X- ........etc to M
+12...................-12
then fill in the blanks with the spreadsheet's functions. Done. Now all you have to do for conversion is match column & row to determine GMT or visa versa.

One other thing, if you make your own time conversion chart, is to highlight the 00:00 in each column...this represents the Date Line. They should show up as diagonals on your chart. So, whenever your rows cross the diagonal it means you've crossed the Date Line...something to be aware of.