A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Jaap vd Heide
Date: 2015 Nov 17, 23:22 -0800
What you would need is some source that would enable you to aquire the GHA (Greenwich hour angle) and the declination of the Sun from the given date and time. After which you can perform the basic calculations Frank referred to, that basically come down to filing in the blanks in the spherical law of cosines.