CFA not recognized?

Hi Jeroen,

To be clear, so the Master calibration frames were made from raw files like canon CR2 or Nikon NEF files?

Why are the light frames of FIT file type? Is this because the frames are acquired with capture software that stored it as Fits?

If these fits files are from capture software then you will need the force CFA setting, but this can only work if the data is monochrome CFA data. Is it monochrome CFA data? or is it already 3 channel data?

Kind regards,

Mabula

Hi Mabula,

all the files (the calibration and als the lights) were indeed captured wit Sequence Generator Pro which saves the data as a FIT.

When I load, for example, a set of dark frames, in the file list under the column "CFA" there's a "NO", but after integration of the masterdark,

the CFA column indicates a "RGGB". The same happens with the BIAS and flat frames (the BPM is a gray scale, which makes sense).

I'm pretty sure the lights are monochrome CFA, because when I open them in another program I see a grayscale image. If you like I can send you an email with a few lights and the master calibration files.

Kind regards,

Jeroen

Hi Jeroen,

Okay, that should be fine then. I have processed a lot of data of DSLR images captured with SGP.

Just make sure that in 0) RAW/FITS the force CFA option is enabled. As you could see from the master frames, they are based on the CFA pixels and are CFA frames themselves. So calibration is done on the CFA pixels like it should.

If you load the lights together with these master frames then it should work if you have the force CFA option enabled. Let me know if it does 😉

Kind regards,

Mabula

Hi Mabula!

I have a QHY8L camera. Should it be possible to see the debayerd raw ligth image? This is a raw .fit file generated with SGP.

dropbox:

Dropbox File (Private or Invalid)

I tried to follow the video "A DSLR data calibration workflow", but it didnt work.

Any Idea what I'm doing wrong?

Kind regards,

Uwe

Hi Uwe,

Detection of whether a frame consists of bayer CFA data depends on the meta data. In this case SGP made the image and is responsible for the metadata. SGP doesn't include a tag for this unfortunately.

SIMPLE  =                    T / file does conform to FITS standard
    BITPIX  =                   16 / number of bits per data pixel
    NAXIS   =                    2 / number of data axes
    NAXIS1  =                 3040 / length of data axis 1
    NAXIS2  =                 2016 / length of data axis 2
    BZERO   =                32768 / offset and data range to that of unsigned short
    BSCALE  =                    1 / default scaling factor
    CRPIX1  =                 1520 / reference spectrum pixel coordinate for axis 1
    CRPIX2  =                 1008 / reference spectrum pixel coordinate for axis 2
    CTYPE1  = 'RA---TAN'           / standard system and projection
    CTYPE2  = 'DEC--TAN'           / standard system and projection
    OBJECT  = 'M27     '           / Object name
    DATE-LOC= '2017-09-27T00:01:52' / Local observation date
    DATE-OBS= '2017-09-26T22:01:52' / UTC observation date
    IMAGETYP= 'LIGHT   '           / Type of frame
    CREATOR = 'Sequence Generator Pro v2.6.0.24' / Capture software
    PROFILE = 'QHY 8L  '           / SGPro profile name
    INSTRUME= 'QHY8L-StarSenseSci' / Instrument name
    FOCUSER = 'Lacerta MotorFocus' / Focuser name
    FOCPOS  =                28410 / Absolute focuser position
    FOCTEMP =     11.3986666666667 / Focuser temperature
    EXPOSURE=                  300 / Exposure time in seconds
    CCD-TEMP=     12.4967683274139 / Camera cooler temperature
    SET-TEMP=      12.907133644924 / Camera cooler target temperature
    XBINNING=                    1 / Camera X Bin
    CCDXBIN =                    1 / Camera X Bin
    YBINNING=                    1 / Camera Y Bin
    CCDYBIN =                    1 / Camera Y Bin
    XPIXSZ  =                  7.8 / Pixel Width in microns (with binning)
    YPIXSZ  =                  7.8 / Pixel Height in microns (with binning)
    TELESCOP= 'Generic Hub'        / Telescope name
    RA      =     299.908246785504 / Object Right Ascension in degrees
    DEC     =     22.7195963374402 / Object Declination in degrees
    CRVAL1  =     299.908246785504 / RA at image center in degrees
    CRVAL2  =     22.7195963374402 / DEC at image center in degrees
    OBJCTRA = '19 59 37.979'       / Object Right Ascension in hms
    OBJCTDEC= '+22 43 10.547'      / Object Declination in degrees
    AIRMASS =     1.39233168137217 / Average airmass
    OBJCTALT=     45.5066666666667 / Altitude of the object
    CENTALT =     45.5066666666667 / Altitude of the object
    FOCALLEN=                  910 / The focal length of the telescope in mm
    FLIPPED =                    F / Is image flipped
    ANGLE   =      272.97969166492 / Image angle
    SCALE   =     1.76428336820608 / Image scale (arcsec / pixel)
    PIXSCALE=     1.76428336820608 / Image scale (arcsec / pixel)
    EGAIN   =                  0.5 / Electrons Per ADU

But it's no big problem, I have downloaded your frame (thank you for that) and checked it.

In 0) RAW/FITS enable the "Force CFA" setting en set the bayer pattern to GBRG, then it is debayered correctly:

Image after debayering:

and zoomed in with background neutralization (N-BG below the histogram):

Kind regards,

Mabula