# Commands

The following page lists all the commands available in Siril 1.2.0.

You can access an index by clicking this icon .

Commands marked with this icon can be used in scripts while those marked with this one cannot.

Tip

For all the sequence commands, you can replace argument sequencename with a `.` if the sequence to be processed is already loaded.

Tip

If you want to provide an argument that includes a string with spaces, for example a filename, you need to quote the entire argument not just the string. So for example you should use `command "-filename=My File.fits"`, not `command -filename="My File.fits"`.

addmax

    addmax filename

Computes a new image combining the image in memory with the image filename. At each pixel location, the new value is determined as the max of value in current image and in filename

asinh

    asinh [-human] stretch [offset]

Stretches the image to show faint objects using an hyperbolic arcsin transformation. The mandatory argument stretch, typically between 1 and 1000, will give the strength of the stretch. The black point can be offset by providing an optional offset argument in the normalized pixel value of [0, 1]. Finally the option -human enables using human eye luminous efficiency weights to compute the luminance used to compute the stretch value for each pixel, instead of the simple mean of the channels pixel values. This stretch method preserves lightness from the L*a*b* color space

autoghs

    autoghs [-linked] shadowsclip stretchamount [-b=] [-hp=] [-lp=]

Application of the generalized hyperbolic stretch with a symmetry point SP defined as k.sigma from the median of each channel (the provided shadowsclip value is the k here and can be negative). By default, SP and the stretch are computed per channel; SP can be computed as a mean of image channels by passing -linked. The stretch amount D is provided in the second mandatory argument.
Implicit values of 13 for B, making it very focused on the SP brightness range, 0.7 for HP, 0 for LP are used but can be changed with the options of the same names

autostretch

    autostretch [-linked] [shadowsclip [targetbg]]

Auto-stretches the currently loaded image, with different parameters for each channel (unlinked) unless -linked is passed. Arguments are optional, shadowclip is the shadows clipping point, measured in sigma units from the main histogram peak (default is -2.8), targetbg is the target background value, giving a final brightness to the image, range [0, 1], default is 0.25. The default values are those used in the Auto-stretch rendering from the GUI.
Do not use the unlinked version after color calibration, it will alter the white balance

bg

    bg

Returns the background level of the loaded image

bgnoise

    bgnoise

Returns the background noise level of the loaded image

binxy

    binxy coefficient [-sum]

Computes the numerical binning of the in-memory image (sum of the pixels 2x2, 3x3..., like the analogic binning of CCD camera). If the optional argument -sum is passed, then the sum of pixels is computed, while it is the average when no optional argument is provided

boxselect

    boxselect [-clear] [x y width height]

Make a selection area in the currently loaded image with the arguments x, y, width and height, with x and y being the coordinates of the top left corner starting at (0, 0), and width and height, the size of the selection. The -clear argument deletes any selection area. If no argument is passed, the current selection is printed

calibrate

    calibrate sequencename [-bias=filename] [-dark=filename] [-flat=filename] [-cc=dark [siglo sighi] || -cc=bpm bpmfile] [-cfa] [-debayer] [-fix_xtrans] [-equalize_cfa] [-opt] [-all] [-prefix=] [-fitseq]

Calibrates the sequence sequencename using bias, dark and flat given in argument.
For bias, a uniform level can be specified instead of an image, by entering a quoted expression starting with an = sign, such as -bias="=256" or -bias="=64*$OFFSET".
By default, cosmetic correction is not activated. If you wish to apply some, you will need to specify it with -cc= option.
You can use -cc=dark to detect hot and cold pixels from the masterdark (a masterdark must be given with the -dark= option), optionally followed by siglo and sighi for cold and hot pixels respectively. A value of 0 deactivates the correction. If sigmas are not provided, only hot pixels detection with a sigma of 3 will be applied.
Alternatively, you can use -cc=bpm followed by the path to your Bad Pixel Map to specify which pixels must be corrected. An example file can be obtained with a find_hot command on a masterdark.
Three options apply to color images (in CFA format): -cfa for cosmetic correction purposes, -debayer to demosaic images before saving them, and -equalize_cfa to equalize the mean intensity of RGB layers of the master flat, to avoid tinting the calibrated image.
The -fix_xtrans option is dedicated to X-Trans images by applying a correction on darks and biases to remove a rectangle pattern caused by autofocus.
It is also possible to optimize the dark subtraction with -opt, which requires both bias and dark masters to be provided.
By default, frames marked as excluded will not be processed. The argument -all can be used to force processing of all frames even if marked as excluded.
The output sequence name starts with the prefix "pp_" unless otherwise specified with option -prefix=.
If -fitseq is provided, the output sequence will be a FITS sequence (single file)

calibrate_single

    calibrate_single imagename [-bias=filename] [-dark=filename] [-flat=filename] [-cc=dark [siglo sighi] || -cc=bpm bpmfile] [-cfa] [-debayer] [-fix_xtrans] [-equalize_cfa] [-opt] [-prefix=]

Calibrates the image imagename using bias, dark and flat given in argument.
For bias, a uniform level can be specified instead of an image, by entering a quoted expression starting with an = sign, such as -bias="=256" or -bias="=64*$OFFSET".
By default, cosmetic correction is not activated. If you wish to apply some, you will need to specify it with -cc= option.
You can use -cc=dark to detect hot and cold pixels from the masterdark (a masterdark must be given with the -dark= option), optionally followed by siglo and sighi for cold and hot pixels respectively. A value of 0 deactivates the correction. If sigmas are not provided, only hot pixels detection with a sigma of 3 will be applied.
Alternatively, you can use -cc=bpm followed by the path to your Bad Pixel Map to specify which pixels must be corrected. An example file can be obtained with a find_hot command on a masterdark.
Three options apply to color images (in CFA format): -cfa for cosmetic correction purposes, -debayer to demosaic images before saving them, and -equalize_cfa to equalize the mean intensity of RGB layers of the master flat, to avoid tinting the calibrated image.
The -fix_xtrans option is dedicated to X-Trans images by applying a correction on darks and biases to remove a rectangle pattern caused by autofocus.
It is also possible to optimize the dark subtraction with -opt, which requires both bias and dark masters to be provided.
The output filename starts with the prefix "pp_" unless otherwise specified with option -prefix=

capabilities

    capabilities

Lists Siril capabilities, based on compilation options and runtime

catsearch

    catsearch name

Searches an object by name and adds it to the user annotation catalog. The object is first searched in the annotation catalogs, if not found a request is made to SIMBAD.
The object can be a solar system object, in that case the prefix 'a:' for asteroid, 'p:' for planet or 'c:' for comet is needed, and the search is done for the date and Earth location found in the image's header, using the IMCCE Miriade service

cd

    cd directory

Sets the new current working directory.
The argument directory can contain the ~ token, expanded as the home directory, directories with spaces in the name can be protected using single or double quotes

cdg

    cdg

Returns the coordinates of the center of gravity of the image. Only pixels with values above 15.7% of max ADU and having four neighbors filling the same condition are used to compute it, and it is computed only if there are at least 50 of them

clahe

    clahe cliplimit tileSize

Equalizes the histogram of an image using Contrast Limited Adaptive Histogram Equalization.
cliplimit sets the threshold for contrast limiting.
tilesize sets the size of grid for histogram equalization. Input image will be divided into equally sized rectangular tiles

clear

    clear

Clears the graphical output logs

clearstar

    clearstar

Clears all the stars saved in memory and displayed on the screen

close

    close

Properly closes the opened image and the opened sequence, if any

convert

    convert basename [-debayer] [-fitseq] [-ser] [-start=index] [-out=]

Converts all images of the current working directory that are in a supported format into Siril's sequence of FITS images (several files) or a FITS sequence (single file) if -fitseq is provided or a SER sequence (single file) if -ser is provided. The argument basename is the base name of the new sequence, numbers and the extension will be put behind it.
For FITS images, Siril will try to make a symbolic link; if not possible, files will be copied. The option -debayer applies demosaicing to CFA input images; in this case no symbolic link is done.
-start=index sets the starting index number, useful to continue an existing sequence (not used with -fitseq or -ser; make sure you remove or clear the target .seq if it exists in that case).
The -out= option changes the output directory to the provided argument.
See also CONVERTRAW and LINK
Links: convertraw, link

convertraw

    convertraw basename [-debayer] [-fitseq] [-ser] [-start=index] [-out=]

Same as CONVERT but converts only DSLR RAW files found in the current working directory
Links: convert

cosme

    cosme [filename].lst

Applies the local mean to a set of pixels on the loaded image (cosmetic correction). The coordinates of these pixels are in a text file [.lst file], the FIND_HOT command can also create it for single hot pixels, but manual operation is needed to remove rows or columns. COSME is adapted to correct residual hot and cold pixels after calibration.
Instead of providing the list of bad pixels, it's also possible to detect them in the current image using the FIND_COSME command
Links: find_hot, find_cosme

cosme_cfa

    cosme_cfa [filename].lst

Same function as COSME but applying to RAW CFA images
Links: cosme

crop

    crop [x y width height]

Crops to a selected area of the loaded image.
If a selection is active, no further arguments are required. Otherwise, or in scripts, arguments have to be given, with x and y being the coordinates of the top left corner, and width and height the size of the selection. Alternatively, the selection can be made using the BOXSELECT command
Links: boxselect

ddp

    ddp level coef sigma

Performs a DDP (digital development processing) on the loaded image, as described first by Kunihiko Okano. This implementation is the one described in IRIS.
It combines a linear distribution on low levels (below level) and a non-linear one on high levels.
It uses a Gaussian filter of standard deviation sigma and multiplies the resulting image by coef. Typical values for sigma are within 0.7 and 2. The level argument should be in the range [0, 65535] for 16-bit images and may be given either in the range [0, 1] or [0, 65535] for 32-bit images in which case it will be scaled automatically

denoise

    denoise [-nocosmetic] [-mod=m] [ -vst | -da3d | -sos=n [-rho=r] ] [-indep]

Denoises the image using the non-local Bayesian algorithm described by Lebrun, Buades and Morel.
It is strongly recommended to apply cosmetic correction to remove salt and pepper noise before running denoise, and by default this command will apply cosmetic correction automatically. However, if this has already been carried out earlier in the workflow it may be disabled here using the optional command -nocosmetic.
An optional argument -mod=m may be given, where 0 <= m <= 1. The output pixel is computed as : out=m x d + (1 − m) x in, where d is the denoised pixel value. A modulation value of 1 will apply no modulation. If the parameter is omitted, it defaults to 1.
The optional argument -vst can be used to apply the generalised Anscombe variance stabilising transform prior to NL-Bayes. This is useful with photon-starved images such as single subs, where the noise follows a Poisson or Poisson-Gaussian distribution rather than being primarily Gaussian. It cannot be used in conjunction with DA3D or SOS, and for denoising stacked images it is usually not beneficial.
The optional argument -da3d can be used to enable Data-Adaptive Dual Domain Denoising (DA3D) as a final stage denoising algorithm. This uses the output of BM3D as a guide image to refine the denoising. It improves detail and reduces staircasing artefacts.
The optional argument -sos=n can be used to enable Strengthen-Operate-Subtract (SOS) iterative denoise boosting, with the number of iterations specified by n. In particular, this booster may produce better results if the un-boosted NL-Bayes algorithm produces artefacts in background areas. If both -da3d and -sos=n are specified, the last to be specified will apply.
The optional argument -rho=r may be specified, where 0 < r < 1. This is used by the SOS booster to determine the amount of noisy image added in to the intermediate result between each iteration. If -sos=n is not specified then the parameter is ignored.
The default is not to apply DA3D or SOS, as the improvement in denoising is usually relatively small and these techniques requires additional processing time.
In very rare cases, blocky coloured artefacts may be found in the output when denoising colour images. The optional argument -indep can be used to prevent this by denoising each channel separately. This is slower but will eliminate artefacts

dir

    dir

Lists files and directories in the working directory
This command is only available on Microsoft Windows, for the equivalent command on Linux and MacOS, see ls.

dumpheader

    dumpheader

Dumps the FITS header of the loaded image in the console

entropy

    entropy

Computes the entropy of the loaded image on the displayed layer, only in the selected area if one has been selected or in the whole image. The entropy is one way of measuring the noise or the details in an image

exit

    exit

Quits the application

extract

    extract NbPlans

Extracts NbPlans planes of wavelet domain of the loaded image.
See also WAVELET and WRECONS. For color extraction, see SPLIT
Links: wavelet, wrecons, split

extract_Green

    extract_Green

Extracts green signal from the loaded CFA image. It reads the Bayer matrix information from the image or the preferences and exports only the averaged green filter data as a new half-sized FITS file. A new file is created, its name is prefixed with "Green_"

extract_Ha

    extract_Ha

Extracts H-Alpha signal from the loaded CFA image. It reads the Bayer matrix information from the image or the preferences and exports only the red filter data as a new half-sized FITS file. A new file is created, its name is prefixed with "Ha_"

extract_HaOIII

    extract_HaOIII [-resample=]

Extracts H-Alpha and O-III signals from the loaded CFA image. It reads the Bayer matrix information from the image or the preferences and exports only the red filter data for H-Alpha as a new half-sized FITS file (like EXTRACTHA) and keeps the three others for O-III with an interpolated replacement for the red pixel. The output files names start with the prefix "Ha_" and "OIII_"
The optional argument -resample={ha|oiii} sets whether to upsample the Ha image or downsample the OIII image to have images the same size. If this argument is not provided, no resampling will be carried out and the OIII image will have twice the height and width of the Ha image

fdiv

    fdiv filename scalar

Divides the loaded image by the image given in argument. The resulting image is multiplied by the value of the scalar argument. See also IDIV
Links: idiv

ffill

    ffill value [x y width height]

Same command as FILL but this is a symmetric fill of a region defined by the mouse or with BOXSELECT. Used to process an image in the Fourier (FFT) domain
Links: fill, boxselect

fftd

    fftd modulus phase

Applies a Fast Fourier Transform to the loaded image. modulus and phase given in argument are the names of the saved in FITS files

ffti

    ffti modulus phase

Retrieves corrected image applying an inverse transformation. The modulus and phase arguments are the input file names, the result will be the new loaded image

fill

    fill value [x y width height]

Fills the loaded image entirely or only the selection if there is one with pixels having the value intensity expressed in ADU

find_cosme

    find_cosme cold_sigma hot_sigma

Applies an automatic detection and replacement of cold and hot pixels in the loaded image, with the thresholds passed in arguments in sigma units

find_cosme_cfa

    find_cosme_cfa cold_sigma hot_sigma

Same command as FIND_COSME but for CFA images
Links: find_cosme

find_hot

    find_hot filename cold_sigma hot_sigma

Saves a list file filename (text format) in the working directory which contains the coordinates of the pixels which have an intensity hot_sigma times higher and cold_sigma lower than standard deviation, extracted from the loaded image. We generally use this command on a master-dark file. The COSME command can apply this list of bad pixels to a loaded image, see also SEQCOSME to apply it to a sequence
Links: cosme, seqcosme
Lines `P x y type` will fix the pixel at coordinates (x, y) type is an optional character (C or H) specifying to Siril if the current pixel is cold or hot. This line is created by the command FIND_HOT but you also can add some lines manually:
Lines `C x 0 type` will fix the bad column at coordinates x.
Lines `L y 0 type` will fix the bad line at coordinates y.

findstar

    findstar [-out=] [-layer=] [-maxstars=]

Detects stars in the currently loaded image, having a level greater than a threshold computed by Siril.
After that, a PSF is applied and Siril rejects all detected structures that don't fulfill a set of prescribed detection criteria, that can be tuned with command SETFINDSTAR.
Finally, an ellipse is drawn around detected stars.
Optional parameter -out= allows the results to be saved to the given path.
Option -layer= specifies the layer onto which the detection is performed (for color images only).
You can also limit the maximum number of stars detected by passing a value to option -maxstars=.
See also CLEARSTAR
Links: psf, setfindstar, clearstar

fix_xtrans

    fix_xtrans

Fixes the Fujifilm X-Trans Auto Focus pixels in the loaded image.
Indeed, because of the phase detection auto focus system, the photosites used for auto focus get a little less light than the surrounding photosites. The camera compensates for this and increases the values from these specific photosites giving a visible square in the middle of the dark/bias frames

fixbanding

    fixbanding amount sigma [-vertical]

Tries to remove the horizontal or vertical banding in the loaded image.
amount defines the amount of correction, between 0 and 4.
sigma defines the highlight protection level of the algorithm, higher sigma gives higher protection, between 0 and 5. Values of 1 and 1 are often good enough.
-vertical option enables to perform vertical banding removal, horizontal is the default

fmedian

    fmedian ksize modulation

Performs a median filter of size ksize x ksize (ksize MUST be odd) to the loaded image with a modulation parameter modulation.
The output pixel is computed as : out=mod x m + (1 − mod) x in, where m is the median-filtered pixel value. A modulation's value of 1 will apply no modulation

fmul

    fmul scalar

Multiplies the loaded image by the scalar given in argument

gauss

    gauss sigma

Applies to the loaded image a Gaussian blur with the given sigma.
See also UNSHARP, the same with a blending parameter
Links: unsharp

get

    get { -a | -A | variable }

Gets a value from the settings using its name, or list all with -a (name and value list) or with -A (detailed list)
See also SET to update values
Links: set

getref

    getref sequencename

Prints information about the reference image of the sequence given in argument. First image has index 0

ght

    ght -D= [-B=] [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels]

Generalised hyperbolic stretch based on the work of the ghsastro.co.uk team.
The argument -D= defines the strength of the stretch, between 0 and 10. This is the only mandatory argument. The following optional arguments further tailor the stretch:
B defines the intensity of the stretch near the focal point, between -5 and 15;
LP defines a shadow preserving range between 0 and SP where the stretch will be linear, preserving shadow detail;
SP defines the symmetry point of the stretch, between 0 and 1, which is the point at which the stretch will be most intense;
HP defines a region between HP and 1 where the stretch is linear, preserving highlight details and preventing star bloat.
If omitted B, LP and SP default to 0.0 ad HP defaults to 1.0.
An optional argument (either -human, -even or -independent) can be passed to select either human-weighted or even-weighted luminance or independent colour channels for colour stretches. The argument is ignored for mono images. Alternatively, the argument -sat specifies that the stretch is performed on image saturation - the image must be color and all channels must be selected for this to work.
Optionally the parameter [channels] may be used to specify the channels to apply the stretch to: this may be R, G, B, RG, RB or GB. The default is all channels

grey_flat

    grey_flat

Equalizes the mean intensity of RGB layers in the loaded CFA image. This is the same process used on flats during calibration when the option equalize CFA is used

help

    help [command]

Lists the available commands or help for one command

histo

    histo channel (channel=0, 1, 2 with 0: red, 1: green, 2: blue)

Calculates the histogram of the layer of the loaded image and produces file histo_[channel name].dat in the working directory.
layer = 0, 1 or 2 with 0=red, 1=green and 2=blue

iadd

    iadd filename

Adds the image filename to the loaded image.
Result will be in 32 bits per channel if allowed in the preferences

idiv

    idiv filename

Divides the loaded image by the image filename.
Result will be in 32 bits per channel if allowed in the preferences.
See also FDIV
Links: fdiv

imul

    imul filename

Multiplies image filename by the loaded image.
Result will be in 32 bits per channel if allowed in the preferences

inspector

    inspector

Splits the loaded image in a nine-panel mosaic showing the image corners and the center for a closer inspection (GUI only)

invght

    invght -D= [-B=] [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels]

Inverts a generalised hyperbolic stretch. It provides the inverse transformation of GHT, if provided with the same parameters, undoes a GHT command, possibly returning to a linear image. It can also work the same way as GHT but for images in negative
Links: ght

invmodasinh

    invmodasinh -D= [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels]

Inverts a modified arcsinh stretch. It provides the inverse transformation of MODASINH, if provided with the same parameters, undoes a MODASINH command, possibly returning to a linear image. It can also work the same way as MODASINH but for images in negative
Links: modasinh

invmtf

    invmtf low mid high [channels]

Inverts a midtones transfer function. It provides the inverse transformation of MTF, if provided with the same parameters, undoes a MTF command, possibly returning to a linear image. It can also work the same way as MTF but for images in negative
Links: mtf

isub

    isub filename

Subtracts the loaded image by the image filename.
Result will be in 32 bits per channel if allowed in the preferences, so capable of storing negative values. To clip negative value, use 16 bit mode or use the THRESHLO command
Links: threshlo

jsonmetadata

    jsonmetadata FITS_file [-stats_from_loaded] [-nostats] [-out=]

Dumps metadata and statistics of the currently loaded image in JSON form. The file name is required, even if the image is already loaded. Image data may not be read from the file if it is the current loaded image and if the -stats_from_loaded option is passed. Statistics can be disabled by providing the -nostats option. A file containing the JSON data is created with default file name '$(FITS_file_without_ext).json' and can be changed with the -out= option

light_curve

    light_curve sequencename channel [-autoring] { -at=x,y | -wcs=ra,dec } { -refat=x,y | -refwcs=ra,dec } ...
    light_curve sequencename channel [-autoring] -ninastars=file

Analyses several stars with aperture photometry in a sequence of images and produces a light curve for one, calibrated by the others. The first coordinates, in pixels if -at= is used or in degrees if -wcs= is used, are for the star whose light will be plotted, the others for the comparison stars.
Alternatively, a list of target and reference stars can be passed in the format of the NINA exolpanet plugin star list, with the -ninastars= option. Siril will verify that all reference stars can be used before actually using them. A data file is created in the current directory named light_curve.dat, gnuplot plots the result to a PNG image if available
The ring radii for aperture photometry can either be configured in the settings or set to a factor of the reference image's FWHM if -autoring is passed.
See also SEQPSF for operations on single star
Links: seqpsf

linear_match

    linear_match reference low high

Computes and applies a linear function between a reference image and the loaded image.
The algorithm will ignore all reference pixels whose values are outside of the [low, high] range

link

    link basename [-date] [-start=index] [-out=]

Same as CONVERT but converts only FITS files found in the current working directory. This is useful to avoid conversions of JPEG results or other files that may end up in the directory. The additional argument -date enables sorting files with their DATE-OBS value instead of with their name alphanumerically
Links: convert

linstretch

    linstretch -BP= [-sat] [channels]

Stretches the image linearly to a new black point BP.
The argument [channels] may optionally be used to specify the channels to apply the stretch to: this may be R, G, B, RG, RB or GB. The default is all channels.
Optionally the parameter -sat may be used to apply the linear stretch to the image saturation channel. This argument only works if all channels are selected

livestack

    livestack filename

Process the provided image for live stacking. Only possible after START_LS. The process involves calibrating the incoming file if configured in START_LS, demosaicing if it's an OSC image, registering and stacking. The temporary result will be in the file live_stack_00001.fit until a new option to change it is added
Links: start_ls

load

    load filename[.ext]

Loads the image filename from the current working directory, which becomes the 'currently loaded image' used in many of the single-image commands.
It first attempts to load filename, then filename.fit, filename.fits and finally all supported formats.
This scheme is applicable to every Siril command that involves reading files

log

    log

Computes and applies a logarithmic scale to the loaded image, using the following formula: log(1 - (value - min) / (max - min)), with min and max being the minimum and maximum pixel value for the channel

ls

    ls

Lists files and directories in the working directory
This command is only available on Unix-like Systems, for the equivalent command on Microsoft Windows, see dir.

makepsf

    makepsf clear
    makepsf load filename
    makepsf save [filename]
    makepsf blind [-l0] [-si] [-multiscale] [-lambda=] [-comp=] [-ks=] [-savepsf=]
    makepsf stars [-sym] [-ks=] [-savepsf=]
    makepsf manual { -gaussian | -moffat | -disc | -airy } [-fwhm=] [-angle=] [-ratio=] [-beta=] [-dia=] [-fl=] [-wl=] [-pixelsize=] [-obstruct=] [-ks=] [-savepsf=]

Generates a PSF for use with deconvolution, any of the three methods exposed by RL, SB or WIENER commands. One of the following must be given as the first argument: clear (clears the existing PSF), load (loads a PSF from a file), save (saves the current PSF), blind (blind estimate of tke PSF), stars (generates a PSF based on measured stars from the image) or manual (generates a PSF manually based on a function and parameters).
No additional arguments are required when using the clear argument.
To load a previously saved PSF the load argument requires the PSF filename as a second argument. This may be in any format that Siril has been compiled with support for, but it must be square and should ideally be odd.
To save a previously generated PSF the argument save is used. Optionally, a filename may be provided (this must have one of the extensions ".fit", ".fits", ".fts" or ".tif") but if none is provided the PSF will be named based on the name of the open file or sequence.
For blind, the following optional arguments may be provided: -l0 uses the l0 descent method, -si uses the spectral irregularity method, -multiscale configures the l0 method to do a multi-scale PSF estimate, -lambda= provides the regularization constant.
For PSF from detected stars the only optional parameter is -sym, which configures the PSF to be symmetric.
For a manual PSF, one of -gaussian, -moffat, -disc or -airy can be provided to specify the PSF function, Gaussian by default. For Gaussian or Moffat PSFs the optional arguments -fwhm=, -angle= and -ratio= may be provided. For Moffat PSFs the optional argument -beta= may also be provided. If these values are omitted, they default to the same values as in the deconvolution dialog. For disc PSFs only the argument -fwhm= is required, which for this function is used to set the diameter of the PSF. For Airy PSFs the following arguments may be provided: -dia= (sets the telescope diameter), -fl= (sets the telescope focal length), -wl= (sets the wavelength to calculate the Airy diffraction pattern for), -pixelsize= (sets the sensor pixel size), -obstruct= (sets the central obstruction as a percentage of the overall aperture area). If these parameters are not provided, wavelength will default to 525nm and central obstruction will default to 0%. Siril will attempt to read the others from the open image, but some imaging software may not provide all of them in which case you will get bad results, and note the metadata may not be populated for SER format videos. You will learn from experience which are safe to omit for your particular imaging setup.
For any of the above PSF generation options the optional argument -ks= may be provided to set the PSF dimension, and the optional argument -savepsf=filename may be used to save the generated PSF: a filename must be provided and the same filename extension requirements apply as for makepsf save filename
Links: psf, rl, sb, wiener

merge

    merge sequence1 sequence2 [sequence3 ...] output_sequence

Merges several sequences of the same type (FITS images, FITS sequence or SER) and same image properties into a new sequence with base name newseq created in the current working directory, with the same type. The input sequences can be in different directories, can specified either in absolute or relative path, with the exact .seq name or with only the base name with or without the trailing '_'

merge_cfa

    merge_cfa file_CFA0 file_CFA1 file_CFA2 file_CFA3 bayerpattern

Builds a Bayer masked colour image from 4 separate images containing the data from Bayer subchannels CFA0, CFA1, CFA2 and CFA3. (The corresponding command to split the CFA pattern into subchannels is split_cfa.) This function can be used as part of a workflow applying some processing to the individual Bayer subchannels prior to demosaicing. The fifth parameter bayerpattern specifies the Bayer matrix pattern to recreate: bayerpattern should be one of 'RGGB', 'BGGR', 'GRBG' or 'GBRG'

mirrorx

    mirrorx [-bottomup]

Flips the loaded image about the horizontal axis. Option -bottomup will only flip it if it's not already bottom-up

mirrorx_single

    mirrorx_single image

Flips the image about the horizontal axis, only if needed (if it's not already bottom-up). It takes the image file name as argument, allowing it to avoid reading image data entirely if no flip is required. Image is overwritten if a flip is made

mirrory

    mirrory

Flips the image about the vertical axis

modasinh

    modasinh -D= [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels]

Modified arcsinh stretch based on the work of the ghsastro.co.uk team.
The argument -D= defines the strength of the stretch, between 0 and 10. This is the only mandatory argument. The following optional arguments further tailor the stretch:
LP defines a shadow preserving range between 0 and SP where the stretch will be linear, preserving shadow detail;
SP defines the symmetry point of the stretch, between 0 and 1, which is the point at which the stretch will be most intense;
HP defines a region between HP and 1 where the stretch is linear, preserving highlight details and preventing star bloat.
If omitted LP and SP default to 0.0 ad HP defaults to 1.0.
An optional argument (either -human, -even or -independent) can be passed to select either human-weighted or even-weighted luminance or independent colour channels for colour stretches. The argument is ignored for mono images. Alternatively, the argument -sat specifies that the stretch is performed on image saturation - the image must be color and all channels must be selected for this to work.
Optionally the parameter [channels] may be used to specify the channels to apply the stretch to: this may be R, G, B, RG, RB or GB. The default is all channels

mtf

    mtf low mid high [channels]

Applies midtones transfer function to the current loaded image.
Three parameters are needed, low, midtones and high where midtones balance parameter defines a nonlinear histogram stretch in the [0,1] range. For an automatic determination of the parameters, see AUTOSTRETCH.
Optionally the parameter [channels] may be used to specify the channels to apply the stretch to: this may be R, G, B, RG, RB or GB. The default is all channels
Links: autostretch

neg

    neg

Changes pixel values of the currently loaded image to a negative view, like 1-value for 32 bits, 65535-value for 16 bits. This does not change the display mode

new

    new width height nb_channel

Creates a new image filled with zeros with a size of width x height.
The image is in 32-bit format, and it contains nb_channel channels, nb_channel being 1 or 3. It is not saved, but becomes the loaded image and it is displayed and can be saved afterwards

nomad

    nomad [limit_magnitude] [-catalog=] [-photo]

Displays stars from the local catalog by default, for the loaded plate solved image, in GUI only, down to the provided limit_magnitude (13 by default).
An alternate online catalog can be specified with -catalog=, taking values tycho2, nomad, gaia, ppmxl, brightstars, apass.
Stars with no B-V information will be kept; they can be excluded by passing -photo

nozero

    nozero level

Replaces null values by level values. Useful before an idiv or fdiv operation, mostly for 16-bit images

offset

    offset value

Adds the constant value (specified in ADU) to the current image. This constant can take a negative value.
In 16-bit mode, values of pixels that fall outside of [0, 65535] are clipped. In 32-bit mode, no clipping occurs

parse

    parse str [-r]

Parses the string str using the information contained in the header of the image currently loaded. Main purpose of this command is to debug path parsing of header keys which can be used in other commands.
Option -r specifies the string is to be interpreted in read mode. In read mode, all wilcards defined in string str are used to find a file name matching the pattern. Otherwise, default mode is write mode and wildcards, if any, are removed from the string to be parsed.
If str starts with $def prefix, it will be recognized as a reserved keyword and looked for in the strings stored in gui_prepro.dark_lib, gui_prepro.flat_lib, gui_prepro.bias_lib or gui_prepro.stack_default for $defdark, $defflat, $defbias or $defstack respectively.
The keyword $seqname$ can also be used when a sequence is loaded

pcc

    pcc [image_center_coords] [-noflip] [-platesolve] [-focal=] [-pixelsize=] [-limitmag=[+-]] [-catalog=] [-downscale]

Run the Photometric Color Correction on the loaded image.
If the image has already been plate solved, the PCC can reuse the astrometric solution, otherwise, or if WCS or other image metadata is erroneous or missing, arguments for the plate solving must be passed:
the approximate image center coordinates can be provided in decimal degrees or degree/hour minute second values (J2000 with colon separators), with right ascension and declination values separated by a comma or a space.
focal length and pixel size can be passed with -focal= (in mm) and -pixelsize= (in microns), overriding values from image and settings.
you can force the plate solving to be remade using the -platesolve flag.
Unless -noflip is specified and the image is detected as being upside-down, the image will be flipped if a plate solving is run.
For faster star detection in big images, downsampling the image is possible with -downscale.
The limit magnitude of stars used for plate solving and PCC is automatically computed from the size of the field of view, but can be altered by passing a +offset or -offset value to -limitmag=, or simply an absolute positive value for the limit magnitude.
The star catalog used is NOMAD by default, it can be changed by providing -catalog=apass. If installed locally, the remote NOMAD (the complete version) can be forced by providing -catalog=nomad
Links: nomad

platesolve

    platesolve [image_center_coords] [-noflip] [-platesolve] [-focal=] [-pixelsize=] [-limitmag=[+-]] [-catalog=] [-localasnet] [-downscale]

Plate solve the loaded image.
If the image has already been plate solved nothing will be done, unless the -platesolve argument is passed to force a new solve. If WCS or other image metadata is erroneous or missing, arguments must be passed:
the approximate image center coordinates can be provided in decimal degrees or degree/hour minute second values (J2000 with colon separators), with right ascension and declination values separated by a comma or a space (not mandatory for astrometry.net).
focal length and pixel size can be passed with -focal= (in mm) and -pixelsize= (in microns), overriding values from image and settings.
Unless -noflip is specified, if the image is detected as being upside-down, it will be flipped.
For faster star detection in big images, downsampling the image is possible with -downscale.
Images can be either plate solved by Siril using a star catalog and the global registration algorithm or by astrometry.net's local solve-field command (enabled with -localasnet).
The following options apply to Siril's plate solve only.
The limit magnitude of stars used for plate solving is automatically computed from the size of the field of view, but can be altered by passing a +offset or -offset value to -limitmag=, or simply an absolute positive value for the limit magnitude.
The choice of the star catalog is automatic unless the -catalog= option is passed: if local catalogs are installed, they are used, otherwise the choice is based on the field of view and limit magnitude. If the option is passed, it forces the use of the remote catalog given in argument, with possible values: tycho2, nomad, gaia, ppmxl, brightstars, apass

pm

    pm "expression" [-rescale [low] [high]]

This command evaluates the expression given in argument as in PixelMath tool. The full expression must be between double quotes and variables (that are image names, without extension, located in the working directory in that case) must be surrounded by the token $, e.g. "$image1$ * 0.5 + $image2$ * 0.5". A maximum of 10 images can be used in the expression.
Image can be rescaled with the option -rescale followed by low and high values in the range [0, 1]. If no low and high values are provided, default values are set to 0 and 1

preprocess

    preprocess sequencename [-bias=filename] [-dark=filename] [-flat=filename] [-cc=dark [siglo sighi] || -cc=bpm bpmfile] [-cfa] [-debayer] [-fix_xtrans] [-equalize_cfa] [-opt] [-all] [-prefix=] [-fitseq]

Calibrates the sequence sequencename using bias, dark and flat given in argument.
For bias, a uniform level can be specified instead of an image, by entering a quoted expression starting with an = sign, such as -bias="=256" or -bias="=64*$OFFSET".
By default, cosmetic correction is not activated. If you wish to apply some, you will need to specify it with -cc= option.
You can use -cc=dark to detect hot and cold pixels from the masterdark (a masterdark must be given with the -dark= option), optionally followed by siglo and sighi for cold and hot pixels respectively. A value of 0 deactivates the correction. If sigmas are not provided, only hot pixels detection with a sigma of 3 will be applied.
Alternatively, you can use -cc=bpm followed by the path to your Bad Pixel Map to specify which pixels must be corrected. An example file can be obtained with a find_hot command on a masterdark.
Three options apply to color images (in CFA format): -cfa for cosmetic correction purposes, -debayer to demosaic images before saving them, and -equalize_cfa to equalize the mean intensity of RGB layers of the master flat, to avoid tinting the calibrated image.
The -fix_xtrans option is dedicated to X-Trans images by applying a correction on darks and biases to remove a rectangle pattern caused by autofocus.
It is also possible to optimize the dark subtraction with -opt, which requires both bias and dark masters to be provided.
By default, frames marked as excluded will not be processed. The argument -all can be used to force processing of all frames even if marked as excluded.
The output sequence name starts with the prefix "pp_" unless otherwise specified with option -prefix=.
If -fitseq is provided, the output sequence will be a FITS sequence (single file)
This command is now deprecated: CALIBRATE should be used instead.
Links: calibrate

preprocess_single

    preprocess_single imagename [-bias=filename] [-dark=filename] [-flat=filename] [-cfa] [-debayer] [-fix_xtrans] [-equalize_cfa] [-opt] [-prefix=]

Calibrates the image imagename using bias, dark and flat given in argument.
For bias, a uniform level can be specified instead of an image, by entering a quoted expression starting with an = sign, such as -bias="=256" or -bias="=64*$OFFSET".
By default, cosmetic correction is not activated. If you wish to apply some, you will need to specify it with -cc= option.
You can use -cc=dark to detect hot and cold pixels from the masterdark (a masterdark must be given with the -dark= option), optionally followed by siglo and sighi for cold and hot pixels respectively. A value of 0 deactivates the correction. If sigmas are not provided, only hot pixels detection with a sigma of 3 will be applied.
Alternatively, you can use -cc=bpm followed by the path to your Bad Pixel Map to specify which pixels must be corrected. An example file can be obtained with a find_hot command on a masterdark.
Three options apply to color images (in CFA format): -cfa for cosmetic correction purposes, -debayer to demosaic images before saving them, and -equalize_cfa to equalize the mean intensity of RGB layers of the master flat, to avoid tinting the calibrated image.
The -fix_xtrans option is dedicated to X-Trans images by applying a correction on darks and biases to remove a rectangle pattern caused by autofocus.
It is also possible to optimize the dark subtraction with -opt, which requires both bias and dark masters to be provided.
The output filename starts with the prefix "pp_" unless otherwise specified with option -prefix=
This command is now deprecated: CALIBRATE_SINGLE should be used instead.
Links: calibrate_single

psf

    psf [channel]

Performs a PSF (Point Spread Function) on the selected star and display the results. For headless operation, the selection can be given in pixels using BOXSELECT. If provided, the channel argument selects the image channel on which the star will be analyzed. It can be omitted for monochrome images or when run from the GUI with one of the channels active in the view
Links: boxselect

register

    register sequencename [-2pass] [-noout] [-drizzle] [-prefix=] [-minpairs=] [-transf=] [-layer=] [-maxstars=] [-nostarlist] [-interp=] [-noclamp] [-selected]

Finds and optionally performs geometric transforms on images of the sequence given in argument so that they may be superimposed on the reference image. Using stars for registration, this algorithm only works with deep sky images. Star detection options can be changed using SETFINDSTAR or the Dynamic PSF dialog. The detection is done on the green layer for colour images, unless specified by the -layer= option with an argument ranging from 0 to 2 for red to blue.
The -2pass and -noout options will only compute the transforms but not generate the transformed images, -2pass adds a preliminary pass to the algorithm to find a good reference image before computing the transforms, based on image quality and framing. To generate transformed images after this pass, use SEQAPPLYREG. -nostarlist disables saving the star lists to disk.
The option -transf= specifies the use of either shift, similarity, affine or homography (default) transformations respectively.
The option -drizzle activates the sub-pixel stacking by up-scaling by 2 the generated images.
The option -minpairs= will specify the minimum number of star pairs a frame must have with the reference frame, otherwise the frame will be dropped and excluded from the sequence.
The option -maxstars= will specify the maximum number of star to find within each frame (must be between 100 and 2000). With more stars, a more accurate registration can be computed, but will take more time to run.
The pixel interpolation method can be specified with the -interp= argument followed by one of the methods in the list no[ne], ne[arest], cu[bic], la[nczos4], li[near], ar[ea]}. If none is passed, the transformation is forced to shift and a pixel-wise shift is applied to each image without any interpolation.
Clamping of the bicubic and lanczos4 interpolation methods is the default, to avoid artefacts, but can be disabled with the -noclamp argument.
All images of the sequence will be registered unless the option -selected is passed, in that case the excluded images will not be processed
If created, the output sequence name starts with the prefix "r_" unless otherwise specified with -prefix= option
Links: setfindstar, psf, seqapplyreg

reloadscripts

    reloadscripts

Rescans the scripts folders and updates the Scripts menu

requires

    requires version

Returns an error if the version of Siril is older than the one passed in argument

resample

    resample { factor | -width= | -height= } [-interp=] [-noclamp]

Resamples the loaded image, either with a factor factor or for the target width or height provided by either of -width= or -height=. This is generally used to resize images, a factor of 0.5 divides size by 2.
In the graphical user interface, we can see that several interpolation algorithms are proposed.
The pixel interpolation method can be specified with the -interp= argument followed by one of the methods in the list no[ne], ne[arest], cu[bic], la[nczos4], li[near], ar[ea]}. If none is passed, the transformation is forced to shift and a pixel-wise shift is applied to each image without any interpolation.
Clamping of the bicubic and lanczos4 interpolation methods is the default, to avoid artefacts, but can be disabled with the -noclamp argument

rgbcomp

    rgbcomp red green blue [-out=result_filename]
    rgbcomp -lum=image { rgb_image | red green blue } [-out=result_filename]

Creates an RGB composition using three independent images, or an LRGB composition using the optional luminance image and three monochrome images or a color image. Result image is called composed_rgb.fit or composed_lrgb.fit unless another name is provided in the optional argument

rgradient

    rgradient xc yc dR dalpha

Creates two images, with a radial shift (dR in pixels) and a rotational shift (dalpha in degrees) with respect to the point (xc, yc).
Between these two images, the shifts have the same amplitude, but an opposite sign. The two images are then added to create the final image. This process is also called Larson Sekanina filter

rl

    rl [-loadpsf=] [-alpha=] [-iters=] [-stop=] [-gdstep=] [-tv] [-fh] [-mul]

Restores an image using the Richardson-Lucy method.
Optionally, a PSF may be loaded using the argument -loadpsf=filename (created with MAKEPSF).
The number of iterations is provide by -iters (the default is 10).
The type of regularization can be set with -tv for Total Variation, or -fh for the Frobenius norm of the Hessian matrix (the default is none) and -alpha= provides the regularization strength (lower value = more regularization, default = 3000).
By default the gradient descent method is used with a default step size of 0.0005, however the multiplicative method may be specified with -mul.
The stopping criterion may be activated by specifying a stopping limit with -stop=
Links: psf, makepsf

rmgreen

    rmgreen [-nopreserve] [type] [amount]

Applies a chromatic noise reduction filter. It removes green tint in the current image. This filter is based on PixInsight's SCNR and it is also the same filter used by HLVG plugin in Photoshop.
Lightness is preserved by default but this can be disabled with the -nopreserve switch.
Type can take values 0 for average neutral, 1 for maximum neutral, 2 for maximum mask, 3 for additive mask, defaulting to 0. The last two can take an amount argument, a value between 0 and 1, defaulting to 1

rotate

    rotate degree [-nocrop] [-interp=] [-noclamp]

Rotates the loaded image by an angle of degree value. The option -nocrop can be added to avoid cropping to the image size (black borders will be added).
Note: if a selection is active, i.e. by using a command `boxselect` before `rotate`, the resulting image will be a rotated crop. In this particular case, the option -nocrop will be ignored if passed.
The pixel interpolation method can be specified with the -interp= argument followed by one of the methods in the list no[ne], ne[arest], cu[bic], la[nczos4], li[near], ar[ea]}. If none is passed, the transformation is forced to shift and a pixel-wise shift is applied to each image without any interpolation.
Clamping of the bicubic and lanczos4 interpolation methods is the default, to avoid artefacts, but can be disabled with the -noclamp argument

rotatePi

    rotatePi

Rotates the loaded image of an angle of 180° around its center. This is equivalent to the command "ROTATE 180" or "ROTATE -180"
Links: rotate

satu

    satu amount [background_factor [hue_range_index]]

Enhances the color saturation of the loaded image. Try iteratively to obtain best results.
amount can be a positive number to increase color saturation, negative to decrease it, 0 would do nothing, 1 would increase it by 100%
background_factor is a factor to (median + sigma) used to set a threshold for which only pixels above it would be modified. This allows background noise to not be color saturated, if chosen carefully. Defaults to 1. Setting 0 disables the threshold.
hue_range_index can be [0, 6], meaning: 0 for pink to orange, 1 for orange to yellow, 2 for yellow to cyan, 3 for cyan, 4 for cyan to magenta, 5 for magenta to pink, 6 for all (default)

save

    save filename

Saves current image to filename.fit (or .fits, depending on your preferences, see SETEXT) in the current working directory. The image remains loaded. filename can contain a path as long as the directory already exists
Links: setext

savebmp

    savebmp filename

Saves current image under the form of a bitmap file with 8-bit per channel: filename.bmp (BMP 24-bit)

savejpg

    savejpg filename [quality]

Saves current image into a JPG file: filename.jpg.
The compression quality can be adjusted using the optional quality value, 100 being the best and default, while a lower value increases the compression ratio

savepng

    savepng filename

Saves current image into a PNG file: filename.png, with 16 bits per channel if the loaded image is 16 or 32 bits, and 8 bits per channel if the loaded image is 8 bits

savepnm

    savepnm filename

Saves current image under the form of a NetPBM file format with 16-bit per channel.
The extension of the output will be filename.ppm for RGB image and filename.pgm for gray-level image

savetif

    savetif filename [-astro] [-deflate]

Saves current image under the form of a uncompressed TIFF file with 16-bit per channel: filename.tif. The option -astro allows saving in Astro-TIFF format, while -deflate enables compression.
See also SAVETIF32 and SAVETIF8

savetif32

    savetif32 filename [-astro] [-deflate]

Same command as SAVETIF but the output file is saved in 32-bit per channel: filename.tif. The option -astro allows saving in Astro-TIFF format, while -deflate enables compression
Links: savetif

savetif8

    savetif8 filename [-astro] [-deflate]

Same command as SAVETIF but the output file is saved in 8-bit per channel: filename.tif. The option -astro allows saving in Astro-TIFF format, while -deflate enables compression
Links: savetif

sb

    sb [-loadpsf=] [-alpha=] [-iters=]

Restores an image using the Split Bregman method.
Optionally, a PSF may be loaded using the argument -loadpsf=filename.
The number of iterations is provide by -iters (the default is 1).
The regularization factor -alpha= provides the regularization strength (lower value = more regularization, default = 3000)
Links: psf

select

    select sequencename from to

This command allows easy mass selection of images in the sequence sequencename (from from to to included). This is a selection for later processing.
See also UNSELECT
Links: unselect

seqapplyreg

    seqapplyreg sequencename [-drizzle] [-interp=] [-noclamp] [-layer=] [-framing=] [-prefix=] [-filter-fwhm=value[%|k]] [-filter-wfwhm=value[%|k]] [-filter-round=value[%|k]] [-filter-bkg=value[%|k]] [-filter-nbstars=value[%|k]] [-filter-quality=value[%|k]] [-filter-incl[uded]]

Applies geometric transforms on images of the sequence given in argument so that they may be superimposed on the reference image, using registration data previously computed (see REGISTER).
The output sequence name starts with the prefix "r_" unless otherwise specified with -prefix= option.
The option -drizzle activates up-scaling by 2 the images created in the transformed sequence.
The pixel interpolation method can be specified with the -interp= argument followed by one of the methods in the list no[ne], ne[arest], cu[bic], la[nczos4], li[near], ar[ea]}. If none is passed, the transformation is forced to shift and a pixel-wise shift is applied to each image without any interpolation.
Clamping of the bicubic and lanczos4 interpolation methods is the default, to avoid artefacts, but can be disabled with the -noclamp argument.
The registration is done on the first layer for which data exists for RGB images unless specified by -layer= option (0, 1 or 2 for R, G and B respectively).
Automatic framing of the output sequence can be specified using -framing= keyword followed by one of the methods in the list { current | min | max | cog } :
-framing=max (bounding box) adds a black border around each image as required so that no part of the image is cropped when registered.
-framing=min (common area) crops each image to the area it has in common with all images of the sequence.
-framing=cog determines the best framing position as the center of gravity (cog) of all the images.
Filtering out images:
Images to be registered can be selected based on some filters, like those selected or with best FWHM, with some of the -filter-* options.
Links: register
With filtering being some of these in no particular order or number:

    [-filter-fwhm=value[%|k]] [-filter-wfwhm=value[%|k]] [-filter-round=value[%|k]] [-filter-bkg=value[%|k]]
    [-filter-nbstars=value[%|k]] [-filter-quality=value[%|k]] [-filter-incl[uded]]

Best images from the sequence can be stacked by using the filtering arguments. Each of these arguments can remove bad images based on a property their name contains, taken from the registration data, with either of the three types of argument values:
- a numeric value for the worse image to keep depending on the type of data used (between 0 and 1 for roundness and quality, absolute values otherwise),
- a percentage of best images to keep if the number is followed by a % sign,
- or a k value for the k.sigma of the worse image to keep if the number is followed by a k sign.
It is also possible to use manually selected images, either previously from the GUI or with the select or unselect commands, using the -filter-included argument.

seqclean

    seqclean sequencename [-reg] [-stat] [-sel]

This command clears selection, registration and/or statistics data stored for the sequence sequencename.
You can specify to clear only registration, statistics and/or selection with -reg, -stat and -sel options respectively. All are cleared if no option is passed

seqcosme

    seqcosme sequencename [filename].lst [-prefix=]

Same command as COSME but for the the sequence sequencename. Only selected images in the sequence are processed.
The output sequence name starts with the prefix "cosme_" unless otherwise specified with option -prefix=
Links: cosme

seqcosme_cfa

    seqcosme_cfa sequencename [filename].lst [-prefix=]

Same command as COSME_CFA but for the the sequence sequencename. Only selected images in the sequence are processed.
The output sequence name starts with the prefix "cosme_" unless otherwise specified with option -prefix=
Links: cosme_cfa

seqcrop

    seqcrop sequencename x y width height [-prefix=]

Crops the sequence given in argument sequencename. Only selected images in the sequence are processed.
The crop selection is specified by the upper left corner position x and y and the selection width and height, like for CROP.
The output sequence name starts with the prefix "cropped_" unless otherwise specified with -prefix= option
Links: crop

seqextract_Green

    seqextract_Green sequencename [-prefix=]

Same command as EXTRACT_GREEN but for the sequence sequencename.
The output sequence name starts with the prefix "Green_" unless otherwise specified with option -prefix=

seqextract_Ha

    seqextract_Ha sequencename [-prefix=]

Same command as EXTRACT_HA but for the sequence sequencename.
The output sequence name starts with the prefix "Ha_" unless otherwise specified with option -prefix=

seqextract_HaOIII

    seqextract_HaOIII sequencename [-resample=]

Same command as EXTRACT_HAOIII but for the sequence sequencename.
The output sequences names start with the prefixes "Ha_" and "OIII_"

seqfind_cosme

    seqfind_cosme sequencename cold_sigma hot_sigma [-prefix=]

Same command as FIND_COSME but for the sequence sequencename.
The output sequence name starts with the prefix "cc_" unless otherwise specified with -prefix= option
Links: find_cosme

seqfind_cosme_cfa

    seqfind_cosme_cfa sequencename cold_sigma hot_sigma [-prefix=]

Same command as FIND_COSME_CFA but for the sequence sequencename.
The output sequence name starts with the prefix "cc_" unless otherwise specified with -prefix= option
Links: find_cosme_cfa

seqfindstar

    seqfindstar sequencename [-layer=] [-maxstars=]

Same command as FINDSTAR but for the sequence sequencename.
The option -out= is not available for this process as all the star list files are saved with the default name seqname_seqnb.lst
Links: findstar

seqfixbanding

    seqfixbanding sequencename amount sigma [-prefix=] [-vertical]

Same command as FIXBANDING but for the sequence sequencename.
The output sequence name starts with the prefix "unband_" unless otherwise specified with -prefix= option
Links: fixbanding

seqght

    seqght sequence -D= [-B=] [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels] [-prefix=]

Same command as GHT but the sequence must be specified as the first argument. In addition, the optional argument -prefix= can be used to set a custom prefix
Links: ght

seqheader

    seqheader sequencename keyword [-out=file.csv]

Prints the FITS header value for the given key for all images in the sequence

seqinvght

    seqinvght sequence -D= [-B=] [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels] [-prefix=]

Same command as INVGHT but the sequence must be specified as the first argument. In addition, the optional argument -prefix= can be used to set a custom prefix
Links: invght

seqinvmodasinh

    seqinvmodasinh sequence -D= [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels] [-prefix=]

Same command as INVMODASINH but the sequence must be specified as the first argument. In addition, the optional argument -prefix= can be used to set a custom prefix
Links: invmodasinh

seqlinstretch

    seqlinstretch sequence -BP= [channels] [-sat] [-prefix=]

Same command as LINSTRETCH but the sequence must be specified as the first argument. In addition, the optional argument -prefix= can be used to set a custom prefix
Links: linstretch

seqmerge_cfa

    seqmerge_cfa sequencename bayerpattern [-prefixin=] [-prefixout=]

Same command as MERGE_CFA but for the sequence sequencename.
The Bayer pattern to be reconstructed must be provided as the second argment as one of RGGB, BGGR, GBRG or GRBG.
The input filenames contain the identifying prefix "CFA_" and a number unless otherwise specified with -prefixin= option.
Note: all 4 sets of input files must be present and must be consistently named, the only difference being the number after the identifying prefix.
The output sequence name starts with the prefix "mCFA_" and a number unless otherwise specified with -prefixout= option
Links: merge_cfa

seqmodasinh

    seqmodasinh sequence -D= [-LP=] [-SP=] [-HP=] [-human | -even | -independent | -sat] [channels] [-prefix=]

Same command as MODASINH but the sequence must be specified as the first argument. In addition, the optional argument -prefix= can be used to set a custom prefix
Links: modasinh

seqmtf

    seqmtf sequencename low mid high [channels] [-prefix=]

Same command as MTF but for the sequence sequencename.
The output sequence name starts with the prefix "mtf_" unless otherwise specified with -prefix= option
Links: mtf

seqpsf

    seqpsf [sequencename channel { -at=x,y | -wcs=ra,dec }]

Same command as PSF but runs on sequences. This is similar to the one-star registration, except results can be used for photometry analysis rather than aligning images and the coordinates of the star can be provided by options.
This command is what is called internally by the menu that appears on right click in the image, with the PSF for the sequence entry. By default, it will run with parallelisation activated; if registration data already exists for the sequence, they will be used to shift the search window in each image. If there is no registration data and if there is significant shift between images in the sequence, the default settings will fail to find stars in the initial position of the search area.
The follow star option can then be activated by going in the registration tab, selecting the one-star registration and checking the follow star movement box (default in headless if no registration data is available).
Results will be displayed in the Plot tab, from which they can also be exported to a comma-separated values (CSV) file for external analysis.
When creating a light curve, the first star for which seqpsf has been run, marked 'V' in the display, will be considered as the variable star. All others are averaged to create a reference light curve subtracted to the light curve of the variable star.
Currently, in headless operation, the command prints some analysed data in the console, another command allows several stars to be analysed and plotted as a light curve: LIGHT_CURVE. Arguments are mandatory in headless, with -at= allowing coordinates in pixels to be provided for the target star and -wcs= allowing J2000 equatorial coordinates to be provided.
Links: psf, light_curve

seqplatesolve

    seqplatesolve sequencename [image_center_coords] [-noflip] [-platesolve] [-focal=] [-pixelsize=] [-limitmag=[+-]] [-catalog=] [-localasnet] [-downscale]

Plate solve a sequence. A new sequence will be created with the prefix "ps_".
If images have already been plate solved, they will just be copied, unless the -platesolve argument is passed to force a new solve. If WCS or other image metadata are erroneous or missing, arguments must be passed:
the approximate image center coordinates can be provided in decimal degrees or degree/hour minute second values (J2000 with colon separators), with right ascension and declination values separated by a comma or a space (not mandatory for astrometry.net). A single catalog extract will be done for the entire sequence, if there is a lot of drift that may not succeed for all images.
focal length and pixel size can be passed with -focal= (in mm) and -pixelsize= (in microns), overriding values from images and settings.
Unless -noflip is specified, if images are detected as being upside-down, they will be flipped.
For faster star detection in big images, downsampling the image is possible with -downscale.
Images can be either plate solved by Siril using a star catalog and the global registration algorithm or by astrometry.net's local solve-field command (enabled with -localasnet).
The following options apply to Siril's plate solve only.
The limit magnitude of stars used for plate solving is automatically computed from the size of the field of view, but can be altered by passing a +offset or -offset value to -limitmag=, or simply an absolute positive value for the limit magnitude.
The choice of the star catalog is automatic unless the -catalog= option is passed: if local catalogs are installed, they are used, otherwise the choice is based on the field of view and limit magnitude. If the option is passed, it forces the use of the remote catalog given in argument, with possible values: tycho2, nomad, gaia, ppmxl, brightstars, apass

seqrl

    seqrl sequencename [-loadpsf=] [-alpha=] [-iters=] [-stop=] [-gdstep=] [-tv] [-fh] [-mul]

The same as the RL command, but applies to a sequence which must be specified as the first argument
Links: rl

seqsb

    sb sequencename [-loadpsf=] [-alpha=] [-iters=]

The same as the SB command, but applies to a sequence which must be specified as the first argument
Links: sb

seqsplit_cfa

    seqsplit_cfa sequencename [-prefix=]

Same command as SPLIT_CFA but for the sequence sequencename.
The output sequences names start with the prefix "CFA_" and a number unless otherwise specified with -prefix= option.
Limitation: the sequence always outputs a sequence of FITS files, no matter the type of input sequence
Links: split_cfa

seqstarnet

    seqstarnet sequencename [-stretch] [-upscale] [-stride=value] [-nostarmask]

This command calls Starnet++ to remove stars from the sequence sequencename. See STARNET
Links: starnet

seqstat

    seqstat sequencename output_file [option] [-cfa]

Same command as STAT for sequence sequencename.
Data is saved as a csv file output_file.
The optional parameter defines the number of statistical values computed: basic, main (default) or full (more detailed but longer to compute).
\tbasic includes mean, median, sigma, bgnoise, min and max
\tmain includes basic with the addition of avgDev, MAD and the square root of BWMV
\tfull includes main with the addition of location and scale.
If -cfa is passed and the images are CFA, statistics are made on per-filter extractions
Links: stat

seqsubsky

    seqsubsky sequencename { -rbf | degree } [-nodither] [-samples=20] [-tolerance=1.0] [-smooth=0.5] [-prefix=]

Same command as SUBSKY but for the sequence sequencename.
Dithering, required for low dynamic gradients, can be disabled with -nodither.
The output sequence name starts with the prefix "bkg_" unless otherwise specified with -prefix= option. Only selected images in the sequence are processed
Links: subsky

seqtilt

    seqtilt sequencename

Same command as TILT but for the sequence sequencename. It generally gives better results
Links: tilt

sequnsetmag

    sequnsetmag

Resets the magnitude calibration and reference star for the sequence. See SEQSETMAG
Links: seqsetmag

seqwiener

    wiener sequencename [-loadpsf=] [-alpha=]

The same as the WIENER command, but applies to a sequence which must be specified as the first argument
Links: wiener

set

    set { -import=inifilepath | variable=value }

Updates a setting value, using its variable name, with the given value, or a set of values using an existing ini file with -import= option.
See GET to get values or the list of variables
Links: get

set16bits

    set16bits

Forbids images to be saved with 32 bits per channel on processing, use 16 bits instead

set32bits

    set32bits

Allows images to be saved with 32 bits per channel on processing

setcompress

    setcompress 0/1 [-type=] [q]

Defines if images are compressed or not.
0 means no compression while 1 enables compression.
If compression is enabled, the type must be explicitly written in the option -type= ("rice", "gzip1", "gzip2").
Associated to the compression, the quantization value must be within [0, 256] range.
For example, "setcompress 1 -type=rice 16" sets the rice compression with a quantization of 16

setcpu

    setcpu number

Defines the number of processing threads used for calculation.
Can be as high as the number of virtual threads existing on the system, which is the number of CPU cores or twice this number if hyperthreading (Intel HT) is available. The default value is the maximum number of threads available, so this should mostly be used to limit processing power. This is reset on every Siril run. See also SETMEM
Links: setmem

setext

    setext extension

Sets the extension used and recognized by sequences.
The argument extension can be "fit", "fts" or "fits"

setfindstar

    setfindstar [reset] [-radius=] [-sigma=] [-roundness=] [-focal=] [-pixelsize=] [-convergence=] [ [-gaussian] | [-moffat] ] [-minbeta=] [-relax=on|off] [-minA=] [-maxA=] [-maxR=]

Defines stars detection parameters for FINDSTAR and REGISTER commands.
Passing no parameter lists the current values.
Passing reset resets all values to defaults. You can then still pass values after this keyword.
Configurable values:
-radius= defines the radius of the initial search box and must be between 3 and 50.
-sigma= defines the threshold above noise and must be greater than or equal to 0.05.
-roundness= defines minimum star roundness and must between 0 and 0.95. -maxR allows an upper bound to roundness to be set, to visualize only the areas where stars are significantly elongated, do not change for registration.
-minA and -maxA define limits for the minimum and maximum amplitude of stars to keep, normalized between 0 and 1.
-focal= defines the focal length of the telescope.
-pixelsize= defines the pixel size of the sensor.
-gaussian and -moffat configure the solver model to be used (Gaussian is the default).
If Moffat is selected, -minbeta= defines the minimum value of beta for which candidate stars will be accepted and must be greater than or equal to 0.0 and less than 10.0.
-convergence= defines the number of iterations performed to fit PSF and should be set between 1 and 3 (more tolerant).
-relax= relaxes the checks that are done on star candidates to assess if they are stars or not, to allow objects not shaped like stars to still be accepted (off by default)
Links: findstar, register, psf

setmag

    setmag magnitude

Calibrates the magnitudes by selecting a star and giving the known apparent magnitude.
All PSF computations will return the calibrated apparent magnitude afterwards, instead of an apparent magnitude relative to ADU values. Note that the provided value must match the magnitude for the observation filter to be meaningful.
To reset the magnitude constant see UNSETMAG
Links: psf, unsetmag

seqsetmag

    seqsetmag magnitude

Same as SETMAG command but for the loaded sequence.
This command is only valid after having run SEQPSF or its graphical counterpart (select the area around a star and launch the PSF analysis for the sequence, it will appear in the graphs).
This command has the same goal as SETMAG but recomputes the reference magnitude for each image of the sequence where the reference star has been found.
When running the command, the last star that has been analysed will be considered as the reference star. Displaying the magnitude plot before typing the command makes it easy to understand.
To reset the reference star and magnitude offset, see SEQUNSETMAG
Links: setmag, seqpsf, psf, sequnsetmag

setmem

    setmem ratio

Sets a new ratio of used memory on free memory.
Ratio value should be between 0.05 and 2, depending on other activities of the machine. A higher ratio should allow siril to process faster, but setting the ratio of used memory above 1 will require the use of on-disk memory, which is very slow and unrecommended, even sometimes not supported, leading to system crash. A fixed amount of memory can also be set in the generic settings, with SET, instead of a ratio
Links: set

setphot

    setphot [-inner=20] [-outer=30] [-aperture=10] [-force_radius=no] [-gain=2.3] [-min_val=0] [-max_val=60000]

Gets or sets photometry settings, mostly used by SEQPSF. If arguments are provided, they will update the settings. None are mandatory, any can be provided, default values are shown in the command's syntax. At the end of the command, the active configuration will be printed. Aperture is dynamic unless forced, the aperture value from settings is not used if dynamic, FWHM is used instead. Gain is used only if not available from the FITS header
Links: seqpsf

setref

    setref sequencename image_number

Sets the reference image of the sequence given in first argument. image_number is the sequential number of the image in the sequence, not the number in the filename, starting at 1

show

    show [-clear] [{ -list=file.csv | [name] RA Dec }]

Shows a point on the loaded plate solved image using the temporary user annotations catalog, based on its equatorial coordinates. The -clear option clears this catalog first and can be used alone. Several points can be passed using a CSV file with the option -file= containing a name (cannot start with a digit), RA and Dec. This is only available from the GUI of Siril

solsys

    solsys [-mag=20.0]

Searches and displays Solar System objects in the current loaded and plate solved image's field of view, using the online IMCCE SkyBoT cone search tool. Use -mag= to change the limit magnitude, defaults to 20

split

    split file1 file2 file3 [-hsl | -hsv | -lab]

Splits the loaded color image into three distinct files (one for each color) and saves them in file1.fit, file2.fit and file3.fit files. A last argument can optionally be supplied, -hsl, -hsv or lab to perform an HSL, HSV or CieLAB extraction. If no option are provided, the extraction is of RGB type, meaning no conversion is done

split_cfa

    split_cfa

Splits the loaded CFA image into four distinct files (one for each channel) and saves them in files

stack

    stack seqfilename
    stack seqfilename { sum | min | max } [filtering] [-output_norm] [-out=filename]
    stack seqfilename { med | median } [-nonorm, -norm=] [filtering] [-fastnorm] [-rgb_equal] [-output_norm] [-out=filename]
    stack seqfilename { rej | mean } [rejection type] [sigma_low sigma_high]  [-rejmap[s]] [-nonorm, -norm=] [filtering] [-fastnorm] [ -weight_from_noise | -weight_from_nbstack | -weight_from_wfwhm | -weight_from_nbstars ] [-rgb_equal] [-output_norm] [-out=filename]

Stacks the sequencename sequence, using options.
Rejection type:
The allowed types are: sum, max, min, med (or median) and rej (or mean). If no argument other than the sequence name is provided, sum stacking is assumed.
Stacking with rejection:
Types rej or mean require the use of additional arguments for rejection type and values. The rejection type is one of n[one], p[ercentile], s[igma], m[edian], w[insorized], l[inear], g[eneralized], [m]a[d] for Percentile, Sigma, Median, Winsorized, Linear-Fit, Generalized Extreme Studentized Deviate Test or k-MAD clipping. If omitted, the default Winsorized is used.
The sigma low and sigma high parameters of rejection are mandatory unless none is selected.
Optionally, rejection maps can be created, showing where pixels were rejected in one (-rejmap) or two (-rejmaps, for low and high rejections) newly created images.
Normalization of input images:
For med (or median) and rej (or mean) stacking types, different types of normalization are allowed: -norm=add for additive, -norm=mul for multiplicative. Options -norm=addscale and -norm=mulscale apply same normalization but with scale operations. -nonorm is the option to disable normalization. Otherwise addtive with scale method is applied by default.
-fastnorm option specifies to use faster estimators for location and scale than the default IKSS.
-rgb_equal will use normalization to equalize color image backgrounds, useful if PCC and unlinked AUTOSTRETCH will not be used.
Other options for rejection stacking:
-weight_from_noise is an option to add larger weights to frames with lower background noise.
-weight_from_nbstack weights input images based on how many images were used to create them, useful for live stacking.
-weight_from_nbstars or -weight_from_wfwhm weight input images based on number of stars or wFWHM computed during registration step.
Outputs:
Result image name can be set with the -out= option. Otherwise, it will be named as sequencename_stacked.fit.
-output_norm applies a normalization to rescale result in the [0, 1] range (median and mean stacking only).
Filtering out images:
Images to be stacked can be selected based on some filters, like manual selection or best FWHM, with some of the -filter-* options.
Links: pcc, autostretch
With filtering being some of these in no particular order or number:

    [-filter-fwhm=value[%|k]] [-filter-wfwhm=value[%|k]] [-filter-round=value[%|k]] [-filter-bkg=value[%|k]]
    [-filter-nbstars=value[%|k]] [-filter-quality=value[%|k]] [-filter-incl[uded]]

Best images from the sequence can be stacked by using the filtering arguments. Each of these arguments can remove bad images based on a property their name contains, taken from the registration data, with either of the three types of argument values:
- a numeric value for the worse image to keep depending on the type of data used (between 0 and 1 for roundness and quality, absolute values otherwise),
- a percentage of best images to keep if the number is followed by a % sign,
- or a k value for the k.sigma of the worse image to keep if the number is followed by a k sign.
It is also possible to use manually selected images, either previously from the GUI or with the select or unselect commands, using the -filter-included argument.

stackall

    stackall
    stackall { sum | min | max } [filtering]
    stackall { med | median } [-nonorm, norm=] [-filter-incl[uded]]
    stackall { rej | mean } [rejection type] [sigma_low sigma_high] [-nonorm, norm=] [filtering] [ -weight_from_noise | -weight_from_wfwhm | -weight_from_nbstars | -weight_from_nbstack ] [-rgb_equal] [-out=filename]

Opens all sequences in the current directory and stacks them with the optionally specified stacking type and filtering or with sum stacking. See STACK command for options description
Links: stack

starnet

    starnet [-stretch] [-upscale] [-stride=value] [-nostarmask]

Calls StarNet to remove stars from the loaded image.
Prerequisite: StarNet is an external program, with no affiliation with Siril, and must be installed correctly prior the first use of this command, with the path to its CLI version installation correctly set in Preferences / Miscellaneous.
The starless image is loaded on completion, and a star mask image is created in the working directory unless the optional parameter -nostarmask is provided.
Optionally, parameters may be passed to the command:
- The option -stretch is for use with linear images and will apply a pre-stretch before running StarNet and the inverse stretch to the generated starless and starmask images.
- To improve star removal on images with very tight stars, the parameter -upscale may be provided. This will upsample the image by a factor of 2 prior to StarNet processing and rescale it to the original size afterwards, at the expense of more processing time.
- The optional parameter -stride=value may be provided, however the author of StarNet strongly recommends that the default stride of 256 be used

start_ls

    start_ls [-dark=filename] [-flat=filename] [-rotate] [-32bits]

Initializes a livestacking session, using the optional calibration files and waits for input files to be provided by the LIVESTACK command until STOP_LS is called. Default processing will use shift-only registration and 16-bit processing because it's faster, it can be changed to rotation with -rotate and -32bits
Note that the live stacking commands put Siril in a state in which it's not able to process other commands. After START_LS, only LIVESTACK, STOP_LS and EXIT can be called until STOP_LS is called to return Siril in its normal, non-live-stacking, state
Links: livestack, stop_ls, exit

stat

    stat [-cfa] [main]

Returns statistics of the current image, the basic list by default or the main list if main is passed. If a selection is made, statistics are computed within the selection. If -cfa is passed and the image is CFA, statistics are made on per-filter extractions

stop_ls

    stop_ls

Stops the live stacking session. Only possible after START_LS
Links: start_ls

subsky

    subsky { -rbf | degree } [-dither] [-samples=20] [-tolerance=1.0] [-smooth=0.5]

Computes a synthetic background gradient using either the polynomial function model of degree degrees or the RBF model (if -rbf is provided instead) and subtracts it from the image.
The number of samples per horizontal line and the tolerance to exclude brighter areas can be adjusted with the optional arguments. Tolerance is in MAD units: median + tolerance * mad.
Dithering, required for low dynamic gradients, can be enabled with -dither.
For RBF, the additional smoothing parameter is also available

synthstar

    synthstar

Fixes imperfect stars from the loaded image. No matter how much coma, tracking drift or other distortion your stars have, if Siril's star finder routine can detect it, synthstar will fix it. To use intensive care, you may wish to manually detect all the stars you wish to fix. This can be done using the findstar console command or the Dynamic PSF dialog. If you have not run star detection, it will be run automatically with default settings.
For best results synthstar should be run before stretching.
The output of synthstar is a fully corrected synthetic star mask comprising perfectly round star PSFs (Moffat or Gaussian profiles depending on star saturation) computed to match the intensity, FWHM, hue and saturation measured for each star detected in the input image. This can then be recombined with the starless image to produce an image with perfect stars.
No parameters are required for this command
Links: psf

threshlo

    threshlo level

Replaces values below level in the loaded image with level

threshhi

    threshi level

Replaces values above level in the loaded image with level

thresh

    thresh lo hi

Replaces values below level in the loaded image with level

tilt

    tilt [clear]

Computes the sensor tilt as the FWHM difference between the best and worst corner truncated mean values. The clear option allows to clear the drawing

unclipstars

    unclipstars

Re-profiles clipped stars of the loaded image to desaturate them, scaling the output so that all pixel values are <= 1.0

unselect

    unselect sequencename from to

Allows easy mass unselection of images in the sequence sequencename (from from to to included). See SELECT
Links: select

unsetmag

    unsetmag

Resets the magnitude calibration to 0. See SETMAG
Links: setmag

unsharp

    unsharp sigma multi

Applies an unsharp mask, actually a Gaussian filtered image with sigma sigma and a blend with the parameter amount used as such: out = in * (1 + amount) + filtered * (-amount).
See also GAUSS, the same without blending
Links: gauss

visu

    visu low high

Displays the loaded image with low and high as the low and high threshold, GUI only

wavelet

    wavelet nbr_layers type

Computes the wavelet transform of the loaded image on (nbr_layers=1...6) layer(s) using linear (type=1) or bspline (type=2) version of the 'à trous' algorithm. The result is stored in a file as a structure containing the layers, ready for weighted reconstruction with WRECONS.
See also EXTRACT
Links: wrecons, extract

wiener

    wiener [-loadpsf=] [-alpha=]

Restores an image using the Wiener deconvolution method.
Optionally, a PSF created by MAKEPSF may be loaded using the argument -loadpsf=filename.
The parameter -alpha= provides the Gaussian noise modelled regularization factor
Links: psf, makepsf

wrecons

    wrecons c1 c2 c3 ...

Reconstructs to current image from the layers previously computed with wavelets and weighted with coefficients c1, c2, ..., cn according to the number of layers used for wavelet transform, after the use of WAVELET
Links: wavelet
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