How to determine when Sun/Moon is aligned to two location on Earth's surface? I would like to make a photo to Moon/Sun when it is very low on horizon, so if I make the shot far away from an object on Earth surface, it appears as big as the Sun.
But how can I calculate the right moment? Any site or app? Could NASA Horizons help? I made a GUI for it, but don't know if any quantity I can query could give me the information  I need:
http://win98.altervista.org/space/exploration/NHUGUI.html
The Photographers Ephemeris is a very nice tool to give you the direction and time of both Moon and Sunset and -rise, made for exactly that purpose: plan and time shots to be at the right place and time for an awesome scenery.
Other programmes and tools to tell you rise and set times are

Stellarium
heavens above
time and date