Al, The easiest way to do it that does not require multiple viewings at separate times is a method that also requires you to know the date and the latitude. But no additional hard calculations or knowledge of the solar time corresponding to the time of the observation.
Using an equatorial-like arrangement of a circle with a perpendicular rod through it's center, adjust the apparatus for your known latitude. Place a mark on the rod corresponding to the tangent of the solar declination (using the radius as unit). Then simply turn the apparatus until the shadow of the rim of the circle hits that mark. It will continue to be on that mark throughout the day. And the apparatus is then aligned to true north. This works well in the early morning and later afternoon. Fred
