I borrowed a PST etalon from my friend and tried some experiments today.
The most exciting one is with a 6.5" ERF, but I only have a C5 on hand... so, my observation is done with 5"!!! This is definitely fun for H-alpha at this aperture!
First one, C5 full aperture at f/10, ~2000 frames stacked:
Another close up, more carefully processed:
All of the prominences: