Recently I bought the Astronomik UHC filter to try and mitigate some of the light pollution problems I had been having. I have not posted a single image that was taken after obtaining this filter although I did do many runs of data acquisition. The problem being that in even data acquisition, after stacking them, I notice these diffraction color bands. At first I thought it was because of the flats, which I corrected as indicated in my last post. And even after that I notice the bands:
After some discussion on the QHYCCD yahoo forum, turns out that this is because of the steep light paths the the f/2 hyperstar system entails, combined with the large CCD chip used to image. The data is there as can be seen from the red channel:

The other channels show severe banding. Green:

And Blue:

As can be seen, the flat looks ok but is just not able to correct for these diffraction bands:

And the bands make it very hard to correct for it and bring out the details. People indicated that the Baader 35nm Halpha filter migt do a better job. The reason being that the steep light path basically shifts the wavelength by about 6nm and this leads to diffraction patters resulting in the color bands. The Baader 35nm, being pretty wide for a Halpha filter still captures the Halpha even though the shift happens and hence should preserve the data while cutting out all the light pollution. I tried stacking them without flats as well, to rule out the flats and the same problem exists. But oh well!! After 200$ for the Astronomik UHC, I think I am back to using the IDAS-LPS-P2
One thing that can be noticed here is that the chip seems to be offcenter. This was indicated by Sander after seeing my flats. I think the collimation effort pushed it a bit off-center. I can try and recollimate to bring it back to the center, but for now I think I am going to continue with this setup and the LPS to see what kind of results I get.