I don't know if this is the right place for this post, if there's a better one let me know.
It seems that whenever I come across a really good shot, the Sun is inevitably in the worst possible position. (You'll find this phenomenon listed under "Flotsam's Law" in the Focal Encyclopedia).

As it is now, I just make a mental note to come back at a different time of day when I guess that the light will be better but this is really a rough estimate especially if the position is critical and I have to hike and get set up before the light peaks.

What I would love to do is be able to take a compass bearing on the scene when I'm there and the light is wrong and then, at home, using a calculator or computer program, determine exactly when the sun will be in it's desired position in relation to the scene so that I can return in plenty of time to set up and catch the light.

Does anyone know of if a program or calculator like this exists? The only ones that I can find only deal with the night sky.