No reason whatsoever not to do this in python, though of course the FFT is just fftw/fftpack and the x/k domain operators are numpy ufuncs (all written in C/Fortran).
On the other hand, for particle simulations, you need more complicated logic/data structures to handle multipole methods, so the python array model might not work so well.
There are tons of optimisation, new representations that can be experimented with for arrays. While NumPy is already reasonably fast, I am convinced you can get much faster by expanding it (within or outside it). String/Object arrays nowhere near as useful as they could be as well.
Hardware time is often cheaper than engineer time, so Python may be faster/cheaper if you consider total time to value.
(I did not wade into that 970 page thread to see if someone had already made a similar suggestion)
I suspect he used something like Stellarium and then ran the images though some filters.
>>> x=Ticktock([2452331.0142361112, 2452332.0142361112], 'JD')
Installation directions for Linux and Windows seem straight-forward.
I'm had many fewer issues with Anaconda, and have found that OS X behaves just as well as Scientific Linux or Mint for stuff like this.
Um... use Anaconda? http://continuum.io/anaconda