I've just started to play with a new brand Chroma 3nm Ha filter and a QHY163M camera.
Waiting for gases to come up, yesterday night I got the Iris nebula rising at NNE just to see what I can get from this setup.
This is a single (unstacked, uncalibrated) stretched (non-linear) frame with Exp=1200s, Gain=180, Offset=60 taken with an old Celestron 8 (orange tube).
Now to my surprise I see nothing but a small nebulosity around the HD20775 star and a lot of noise!
I know I have to take a lot of images to get enough signal but I was expecting something more...
What I'm doing wrong?