Lost at Sea
For the Really Expert Experts
Using trigonometry to Find the Declination
If the sailors did not have access to Declination tables, they can calculate the angle of declination using the formula below:
where:
δ is the declination when cos operates on degrees;
if cos operates on radians, 360° in the equation needs to be replaced with 2π and will still output δ in degree;
N is Day of the Year, that is the number of days spent since January 1.
From http://en.wikipedia.org/wiki/Declination