I just finished a program that computes the positions of the planets and Moons using the huge VSOP87 dataset. Despite this dataset (almost 500kb for Mercury alone - there are 8 more) the executable is *only* 1MB in size. It also took the compiler only a second to compile close to 40,000 lines of code.
The program can search for any planetary alignment not just heliocentric or geocentric. So imagine you are on Jupiter and you want to know when the next time will be when you see Uranus and Neptune conjunct. This alignment is pretty rare. The last time it occurred was in 1991. The next time it will occur is in 2167. It took the program ONLY 5 SECONDS to find it.
If you have no clue as to whether or not this is fast, just have a look at the VSOP87 tables.


