My apologies if this has been covered already, but I've been having some issues stacking images taken with my recently-acquired Svbony CLS filter clip-in filter. Briefly, it's installed in my unmodified Canon T3i and I've noticed the problem with both my 80mm achromat and my 50mm canon lens.
While I understand that red is greatly reduced when using a CLS filter, I seem to have a modest amount of red captured in my light frames:
Canon RAW file: https://www.dropbox....tf_cls.CR2?dl=0
JPG file: https://www.dropbox....tf_cls.jpg?dl=0
But by the time it is stacked (I'm using SiriL) almost all the red data is gone, and it's reduced to just pin-point stars, even when stretched. I have good data in my blue and green channels, but I can't balance the colour without the red data. Photometric colour calibration sometimes helps create usable images, but I'm wondering why my red data has gone? Is it all noise?
Stacked FIT file, no processing: https://www.dropbox....etched.fit?dl=0
The CLS filter seems to be increasing the chromatic fringing around stars (on my achromat) and I'm often having to deal with plenty of colourful gradients. Is my cheap CLS filter to blame? Is the processing/SiriL to blame? Is this compression of red data totally normal? I'm kind of baffled. I'm including a link to one of my flats, below, taken with the filter in:
Canon RAW file: https://www.dropbox....at_cls.CR2?dl=0
JPG file: https://www.dropbox....at_cls.jpg?dl=0
Should I stop using the filter, and if so, should I switch to another filter? Modifying my camera is not really an option now, but perhaps down the road.
I'd appreciate any advice/input. Thanks!