Horsehead in quasi-h-alpha.

I have been struggling with light pollution from my roof-top veranda in the middle of Oslo. I have tried light pollution filters, but have been dissatisfied with the results. Maybe I am doing it wrong. I have been thinking of bying a set of narrow-band filters for the usual suspects : H-alpha, OIII and H-beta. But those would only be usable for the telescopes. Not my tele-photo lenses. And I really wanted to use those too with such filters. Especially for large nebula structures. But such filters do not exists in the sizes needed (82mm). So I had this idea. What if I use a light pollution filter in conjunction with an ordinary color enhancer filter? I found filter types that would filter out the different parts of the LPS spectrums. I have an 82mm IDAS LPS-P2 filter for my telephoto lenses.
This weekend, I wanted to try a filter I had bought on e-bay. An IR630 filter. This is supposed to filter out everything below 630nm. And thus, the only thing left in the LP-flter, is the H-alpha and SII area. I have tried an 091 deep red filter with a 85mm lens. But I need to stop it down more to get good results. But it showed very much promise. Now I bought the IR630 in both 46 and 82mm edition. The 46 for my telescope. It is slightly deeper red than the 091. I attached the IR630 to my Astronomik CLS filter through a 48-46 adapter, and attached this to the field flattener of my APO.
I waited for the skies to clear, and managed to get about 2 hours worth of 2 minute exposures. Stacked them in DSS and processed the final image with DDP. Then some processing in Gimp. The result is VERY satisfying. Although this is nothing compared to a narrowband image on a mono CCD, I am pleased with the result, given the short exposure. The two other wavelengths, H-beta and OIII are currently more difficult to obtain, since I haven't found a proper filter for this. But I am planning to try to aquire a filter that filters out everything above around 510 nm. Then the CLS filter should do the rest.
Technical data :
Pentax K5, ISO 1600, TS triplet APO w/ WO field flattener, Celestron AVX, 60x2min unguided. 20 flats. Stacked in DSS, processed in Gimp. Reduced to 50%.