QHY8L Different Bayer Pattern in BPP and manual Image Integration

[Herzogu]

Hello to all!

I'm working with a QHY8L OSC.
When I'm using the Script "Batchpreprocessing and choose "GBRG" as the correct Bayer Pattern for the QHY8L, I get results like attached "NGC4443_BPP_GBRG", red and green channel are changed.
To get a plausible result, I've to choose "RGGB" as Bayer Pattern, like in attached "NGC4443_BPP_RGGB.jpg".
For the manual Image Integration Bayer Pattern "GBRG" is working fine.
I have installed PI 01.08.03.1123 and checked this several times.

Best regards from Muenster/Germany,

Uli

This is confusing me a little bit, and maybe nice to know for developers and other users of QHY8L.
 

[pfile]

this is likely a problem with the FITS reader direction - the FITS explorer settings are probably being overriden by BPP. only one direction is correct and should correspond with the published bayer pattern for that camera.

rob

[tango13]

Hello all,

I'm sorry to revive this old thread but I'm having exactly the same problem and I don't understand if I should handle it in some special way.
Is this a bug in the software or is the CCD responsible for writing a wrong FITS header?
Or something else?
I'm too a bit confused like Herzogu was.

Thank you.
Piero

[pfile]

there's no standard for which corner of the image the 0th byte of a FITS file corresponds to. so you have to figure out by trial and error what your capture software is doing and set PI appropriately.

rob

[tango13]

Hi Rob and thanks for the answer.
As far as I know the bayer matrix for the QHY8L is GBRG and other software behave correctly when I use such a scheme.
The problem with PI I asked about is that, if I use BatchPreProcessing, to get correct results I have to use the RGGB pattern, whereas if I use directly the Debayer function on the same images I have to use the GBRG pattern to get the same correct results.
Not a big deal, as long as I now know this, but is it a normal behavior?

Thank you.
Piero

[pfile]

well so the module that handles fits files sets the reader direction in two ways. one is the reader direction that's set in the FITS file handler itself. if you open an image onto the desktop, that is the reader direction used.

however, many PI processes take "format hints" which can be used to override the file handler setting. a format hint is used by BPP to change the FITS reader direction, and in PBB the format hint is controlled by the check box on the main BPP interface that says "up-bottom FITS". if you toggle the state of that checkbox, GBRG should work right with BPP.

rob

[tango13]

Ahhh ok I see, great explanation Rob!
Thank you very much.

Piero