jacobsonc Without filters or cropping the best fit was RGBG in both PI and AstroArt 9.
Bayer pattern is based on the camera sensor, and not dependent on the filter.
A Sony sensor based CMOS sensor uses the
RG
GB
pattern as the Bayer filter. Most programs call it RGGB.
If you flip the image upside down, because most sensors have an even number of pixels for their height, the Bayer pattern becomes
GB
RG
(or, most programs will call it GBRG).
When you crop an image, it depends on whethet yu have cropped it at an even x-y pixel bpunday or odd pixel boundary. An even pixel bounday crop will still have RGGB, while an odd boundary crop will need GBRG debayering.
By the way, if you look at most camera's Bayer filters, you will find that the response of the OIII and Hbeta pair near 500nm will both exicite the blue and green pixels to about the same amount (look at where the blue and green color curves intersect).
What this means is that your 4-band filter will not be able to distinuish OIII from Hbeta. In regions that have strong Hydrogen, what happens is that the Hbeta will swamp the OIII, and together with the usually strong Halpha (red pixels). What you end up an image that is rmostly red and pink. And hard to extract any of the pretty blue colors from the OIII.
This is why most good filters today are dual band (i.e. pass Halpha and OIII only), so that there is no contamination from Hbeta. (There are some Sulphur/Hbeta dual band filters, but those also don't include both OIII and Hbeta at the same time).
The Radian ultra is good with (lack of) halos, but not easy to process into a pretty image, and that OIII/Hbeta contamination could be what is confusing you with your debayering selection.
Except for filter testing, I have stopped using my Radian Quad Ultra sometime back. I even still have a second one that is 52mm for Borg telescopes instead of the more common 48mm filter thread.
Chen
