Thank you, kevin,
Theoretical response of original filter and my others. 25% of transmission in H-alfa region.
If you want a photo with visual impact ... it is poor. But to obtain information about the object, with DSLR that work with ISO, you can some result with it and total time of exposure.
I think the major problem is that you haven't 100% of pixel to catch the information as mono camera has. But there is improvement when the capture is HalfaRGB.
Mask and HDR can enhance this improvement. This will be the goal of my tests. I never did process with narrowband filters. I am just trying and learning about this task.
Nevertheless, the correct solution is:to buy a good mono camera, a good Halfa filter and go to a site with good dark-clear sky. Easy, no ?
