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Bayer Pattern Changing???

13 May, 2019 18:23
Hi guys,
    Hopefully someone can shed some light on a problem I am having when loading my subs to Deep Sky stacker.  So some contextual; background, I am using a ZWO ASI178MC-Cool for imaging.  I use ASICAP for acquisition for its simplicity, I have tried APT but it just adds a whole new level of complexity.  Long story short, I'm keeping my capture methods simple so I can focus on getting a feel for the settings and obtaining as much data as possible    I use the 16-Raw setting which requires me to check the "Monochrome 16 bit FITS Files…" in DSS.  My camera has a bayer matrix of RGGB, and for the last 6 months I have kept that box checked and received no problems.  However, recently I noticed that my subs are coming out the wrong color, I am having to change the pattern setting in DSS to BGGR.  The strange thing is that one set of subs will be in the original RGGB then anther in BGGR.  I cant find what it is that is causing the change as the captured images will flip in between sub sets on the same night.  I always thought the matrix was static inside the camera, is this incorrect? Hopefully you guys can help, I can work around it but it is kind of a pain.,
   Thanks and much love,
      John Michael Bellisario
13 May, 2019 19:17
Hi John,

the bayer matrix IS static in the camera, it is "hardware" like a filter directly in front of your chip. But different softwares read out the bayer pattern in different directions. So a pattern like
can be interpreted as RGGB (top left to bottom right) or BGGR (bottom right to top left) or even GRBG (top right to bottom left) or anything else.
So did you perform an update on any software you used for capturing or processing? That is the only way i can imagine that the pattern changes in the same piece of software.
I hope that my thoughts might help and i also hope that i am correct with what i wrote - these bayer-patterns often confuse me. It took me about a month or so to figure out which software uses which direction when debayering the images from my ASI178MC. I ended up with a more or less complex Excel chart after endless trial-and-error-sessions :-)

Edited 13 May, 2019 19:21
13 May, 2019 20:04
Hi Michael,
 Thanks for your input, it reinforced my initial thoughts. I picked up a new laptop just for aquisition, so I'm guessing it was either that or one of the many updates I've done. So I'm struggled to diagnose the source of the bayer matrix swap because I haven't found any pattern withing the error.  FOR EXAMPLE, last night framed up M57 and imaged 20 subs, I then slewed to m20 and finished out the remainder or the night imaging the Trifid. All the setting were the same, the only changes I made between sets was the destination folder. This morning when I loaded them into DSS M57 was color Correct with the RGGB matric selected but M20 was inverted and I had to switched the setting to BGGR.  This seems to be the case with all of my subs lately, some are one and some are the other.  I Thought maybe it was meridian flips but that doesn't make much sense because DSS is not coordinate bias, or is it?
13 May, 2019 20:12
No, the flip makes no sense for your strange problem. Could you give me access to an unprocessed fits file of each M57 and M20 (via DropBox, GoogleDrive or anything else?)
13 May, 2019 20:18
Ya I can when I get home from work
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