Roger, you are correct. It is not that difficult. The problem is that so far it has simply not been done.

What I am presently attempting to do is get a subroutine written which takes the UTC time and generates the subsolar and sublunar data and similar data for the planets and then returns it to the main program. The necessary information is available from Web sites such as the following ones. It is a matter of getting the necessary calculations identified and the subroutine written.

http://www.stjarnhimlen.se/comp/ppcomp.html

http://www.astro.com/