When Will The Moon Be There Again?

While driving this evening sometime between sunset and the end of civil twilight, my two-and-a-half-year-old son noticed a blood-red, rising full moon. Upon seeing it, I immediately felt disappointed for not having my camera with me to photograph it in the midst of this particular farmland scene. I began to wonder when the full moon would be in that position again, which led me to begin thinking about how to solve the problem.

In theory, it seems there should be a fairly straightforward solution. First, determine the apparent azimuth and elevation (which may or may not be that easy; I cheated and used Planetarium, my Palm-based astronomy application) at the time of observation. The solution could then be determined by iteration or by rewriting the position determination equations to accept the azimuth, elevation, and position information. The former seems easiest to implement, but much more resource-intensive. The latter seems exceedingly difficult (at least for me) to implement, but would be preferred because of the ability to perform a direct calculation of the solution. If I have some time, I'll try to solve the problem using both methods.