Lovely image there. I take it you were using the SBIG Adaptive Optics system, they are a great idia, especially on lesser quality mounts, I believe they can easily account for a few mins of periodic error with pin sharp images.
What focal ratio was that image shot at? Its amazing that it requires 1 hour sub exposures to get through the H alpha filter.?
Heres a 2x 20 minute shot I took with an unmodified Canon 300D , 10 inch F5,6 newtonian and a 7 nm Ha filter of Eta carina
http://www.users.on.net/~josiah/baad...ha%20small.jpg
Now if I can just get a hold of a narrowband SII and OIII filter....
Scott