Hi George
From my understanding the sigma clipping only removes noise as " unwanted pixels from things like hot pixels plane trails etc " the noise reduction comes from std average stacking of you images ( This part is no better than other programs as its simple maths )
I
Harry
I find the rejection integration and integration is much more powerful the most if not all programs I have tried.
It does more than removing airplane trials. It will improve you image's S/N if done right.
You should dither your sub images to receive the Maxium benifit.
Generally 1-1.5 or less percent are need to be rejected.
This varies a lot sky conditions, dither, camera etc. 25% rejection is way to much.
If you have CCD with fewer hot pixels you will see/ need less % rejected.
My CCD is fairly easy to see if the rejection is good. The sensor is big enough there are plenty of cosmic ray hits and often a sat. trial to reject. I move the slider up until they are pretty much gone. I see the result on the high Map after STF.
I watch the S/N outputs on consul if you doing better then numbers decrease. I wish knew more about the consul output. Ie S/N verses S/N increament. Someday they will let me in on the secret.
Max
