I am hoping to use Siril for images captured by a ZWO ASI585MC camera. When I bring the FITS files into Siril I see a square pixel pattern as shown in the attachment. I do not see this on FITS viewers. Any suggestions?
We need much more information.
Looks like a wrong demosaicing but without more information about what you have done, or a file example. This is difficult to say.
Thank you for your comments.
I am using AsiAir with the ZWO 585 based camera, 16 bit images and no dithering. When opening the FITs images with Siril I check the debayer box on the conversion tab. The preferences for FITS debayer are left as default settings. When opening a single file or stacked images I see the same artifact.
Advice much appreciated. I am unable to upload a FITs file, please let me know if any additional information that will be useful.
Please share a file. There are plenty of way of sharing files (weTransfer,…)
Thanks I will do so. Fits header is
SIMPLE = T / file does conform to FITS standard
BITPIX = 16 / number of bits per data pixel
NAXIS = 2 / number of data axes
NAXIS1 = 3840 / length of data axis 1
NAXIS2 = 2160 / 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 = 0. / Offset data range to that of unsigned short
BSCALE = 1. / Default scaling factor
PROGRAM = ‘Siril 1.4.0-beta2’ / Software that created this HDU
DATE = ‘2025-06-14T14:57:16’ / UTC date that FITS file was created
DATE-OBS= ‘2025-06-10T23:33:24.380113’ / YYYY-MM-DDThh:mm:ss observation start,
IMAGETYP= 'Light ’ / Type of image
EXPTIME = 60. / [s] Exposure time duration
TELESCOP= 'ZWO AM3 ’ / Telescope used to acquire this image
FOCALLEN= 702. / [mm] Focal length
XBINNING= 1 / Camera binning mode
YBINNING= 1 / Camera binning mode
YPIXSZ = 2.90000009536743 / [um] Pixel Y axis size
INSTRUME= ‘ZWO ASI585MC Pro’ / Instrument name
CCD-TEMP= -19.2000007629395 / [degC] CCD temperature
SET-TEMP= -20. / [degC] CCD temperature setpoint
GAIN = 255 / Sensor gain
OFFSET = 15 / Sensor gain offset
CVF = 0.499031364917755 / [e-/ADU] Electrons per A/D unit
BAYERPAT= 'RGGB ’ / Bayer color pattern
OBJECT = 'M51 ’ / Name of the object of interest
SITELAT = 50.7129 / [deg] Observation site latitude
SITELONG= -1.92845 / [deg] Observation site longitude
RA = 202.737495 / [deg] Image center Right Ascension
DEC = 47.065278 / [deg] Image center Declination
CREATOR = ‘ZWO ASIAIR Mini’ / Capture software
XORGSUBF= 0 / Subframe X position in binned pixels
YORGSUBF= 0 / Subframe Y position in binned pixels
CCDXBIN = 1 / Camera X Bin
CCDYBIN = 1 / Camera Y Bin
GUIDECAM= ‘ZWO ASI120MM Mini’ / Guide camera model
END