Fits Header Info missing Filter Type.
Like for Filters LRGB SHO each file is missing the Filter so calibrating fails as stacking based on Filter Type.
SIMPLE = T / file does conform to FITS standard
BITPIX = 16 / number of bits per data pixel
NAXIS = 2 / number of data axes
NAXIS1 = 9576 / length of data axis 1
NAXIS2 = 6388 / length of data axis 2
EXTEND = T / FITS dataset may contain extensions
COMMENT FITS (Flexible Image Transport System) format is defined in 'Astronomy
COMMENT and Astrophysics', volume 376, page 359; bibcode: 2001A&A...376..359H
BZERO = 32768.000000000000 / physical = BZERO + BSCALEarray_value
BSCALE = 1.0000000000000000 / physical = BZERO + BSCALEarray_value
XBINNING = 1 / Binning factor in width
YBINNING = 1 / Binning factor in height
EXPOINUS = 180000000 / Exposure time in us
GAIN = 100 / The ratio of output / input
OFFSET = 50 / Brightness(offset) of image
WB_RED = 0 / White Balance(Red)
WB_BLUE = 0 / White Balance(Blue)
CBLACK = 0 / Initial display black level in ADUs
CWHITE = 65535 / Initial display white level in ADUs
PEDESTAL = 0 / Correction to add for zero-based ADU
SWCREATE = 'ASIImg ' / Name of software that created the image
DATE-OBS = '2024-09-29T07:59:21.531' / UTC start date of observation
DATE-STA = '2024-09-29T07:59:21.531' / UTC start date of exposure
DATE-END = '2024-09-29T08:02:21.531' / UTC end date of exposure
BAYERPAT = 'NONE ' / Debayer pattern,such as RGGB,BGGR,GRBG,GBRG
COLORTYP = 'RAW16 ' / Color space, such as RAW8,RAW16,RGB24
INPUTFMT = 'FITS ' / Format of file from which image was read
INSTRUME = 'ZWO ASI6200MM Pro' / Camera model
XPIXSZ = 3.76 / Pixel Width in um
YPIXSZ = 3.76 / Pixel Height in um
EXPOSURE = 180. / Exposure time in seconds
EXPTIME = 180. / Total Exposure Time (s)
CCD-TEMP = -9.8 / CMOS sensor temperature in C
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I added the Filter to each file.
FILTER = 'L ' / Filter used when taking image
