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
any thoughts on this? thank you
Hi,
Can you show a snapshot of Preferences->FITS/SER Debayer. If I leave everything to default, it opens fine. If I untick this box:
I see a pattern indicating it was not correctly debayered. So this box needs to be ticked.
BTW, Probably woth reporting to ZWO that they could use the ROWORDER key so that any software reading their image would know how the bayer pattern is to be interpreted (see our doc here: FITS — Siril 1.4.0-beta1 documentation)
Cheers,
C
thank you I will give this a try and let you know. Much appreciated
I have confirmed the setting in preferences and the top-down box is checked. You can see from the image I unfortunately still have the problem. I have passed on the message to ZWO.
Here you are opening your file without demosaicing. This is normal to see Bayer pattern.
I see, yes the stacked image looks fine now. Thank you for your help, very much appreciated