The original recording was put through a Wave - MIDI converter program and re-worked from there. These converter programs are notoriously haphazard, but that actually suits my purposes as they can produce some quite amazing sounds if controlled carefully. You just have to learn to expect the unexpected!
The final result could be described as sounding like a quartet of guitars shining like scintillating beacons through a hazy nebula that shifts and shimmers, bending and twisting the notes slightly. That's the best explanation I can come up with at the moment, anyway! As soon as I had the basic sound right it immediately made me think of the Pleiades star cluster, hence the title. The MIDI file is missing the extra effects and probably sounds a bit of a jumble, but I've put it here for comparison. It is basically the framework for the finished mp3 version (and full frequency WAV file for the subsequent CD). Of course, as with every new piece I do, this isn't necessarily the final version, I might tinker with it some more.
I'm dedicating this piece to Phil Plait, writer of the excellent Bad Astronomy website. I've got no idea what his taste in music is, but I hope he likes this nevertheless.
Download mp3 or 
MIDI framework