Revision as of 20:21, 31 December 2013 by Lock42 (talk | contribs) (Add of new commands: findstar, clearstar)

Siril command line functions reference

This manual is a summary of the different commands you can find in Siril. As Siril is in alpha test phase, numerous commands can be added and some others can be changed. Please check the date of the page (the history link) before using.


addmax filename

addmax compute a new image IMG with IMG_1 and IMG_2. The pixel of IMG_1 is replaced by the pixel at the same coordinates of IMG_2 if the intensity of 2 is greater than 1. Do not forget to save the result.



Return the background level of the image loaded in memory.


cd directory

Set the current working directory.



Clear all the stars saved in memory and displayed on the screen.


crop x, y, width, height

Crops the current image within the rectangle previously selected.


ddp level coef sigma

Performs a DDP (digital development processing) 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 on high levels. It uses a Gaussian filter of sigma sigma multiplies the resulting image by coef.


entropy filename

Computes the entropy of the file given in the parameter filename.



Quits the application.


fdiv filename scalar

Divides the image in memory by the image given in argument. The resulting image is multiplied by the value of the scalar argument. Please check that the image is in the working directory. See also fdiv.


fill value

Fills the whole current image with pixels having the value intensity.


fill value x y width height

Same command than fill but only the pixels within the selection are filled with the value intensity.



Detects stars having a level greater than a threeshold computed by Siril. The algorithm is based on the publication of Mighell, K. J. 1999, in ASP Conf. Ser., Vol. 172, Astronomical Data Analysis Software and Systems VIII, eds. D. M. Mehringer, R. L. Plante, & D. A. Roberts (San Francisco: ASP), 317.

After that, a dynamic PSF is applied and Siril rejects all detected structures that don't fulfill a set of prescribed detection criteria. Finaly, a circle is drawn around detected stars. See also the command clearstar.


gauss sigma

Performs a Gaussian filter with the given sigma.



Gives the available commands.


histo layer

Calculates the histogram of the image layer in memory and produces file histo_[layer name].dat in the working directory.

layer = 0, 1 or 2 with 0=red, 1=green and 2=blue.


iadd filename

Adds the image in memory to the image designed in argument. Please check that the image is in the working directory.


idiv filename

Divides the image in memory by the image given in argument. Please check that the image is in the working directory. See also fdiv.


imul filename

Multiplies the image in memory by the image given in argument. Please check that the image is in the working directory.


isub filename

Substracts the image in memory by the image given in argument. Please check that the image is in the working directory.


load filename
load filename.ext

Loads the fits image filename; it first attempts to load filename, then and finally filename.fits and after, all supported format, aborting if none of these are found. These scheme is applicable to every Siril command implying reading files. Fits headers MIPS-HI and MIPS-LO are read and their values given to the current viewing levels.

Writing a known extension at the end of filename will load the image filename.ext: this is used when numerous files have the same name but not the same extension.

Extensions supported are :

  • *.fit, *.fits, *.fts
  • *.bmp / *.jpg, *.jpeg / *.png / *.tif, *.tiff
  • *.ppm, *.pgm
  • *.pic (IRIS file)



Computes and applies a logarithmic scale to the current image.



Rotates the image around a vertical axis.



Rotates the image around an horizontal axis.


new width height

Creates a new image filled with zeros with a size of width height.


nozero level

Replaces null values by level values. Useful before an idiv or fdiv operation.


offset value

Adds the constant value to the current image. This constant can take a negative value. As Siril uses unsigned fit files, if the intensity of the pixel become negative its value is replaced by 0 and by 65535 (for a 16-bit file) if the pixel intensity overflows. To check the minimum and maximum intensities values, click on the Auto level button and note the low and high threshold.



Make a selection around a star and call the command PSF. It will give you:

  • The centroid coordinates in pixel units, which is the position of the center of symmetry of the fitted PSF.
  • The FWHM on the X and Y axis.
  • The average local background.
  • The relative magnitude of the star.

To be relevant, the selection MUST be done on a non-saturated star.



Rotates the image of an angle of 180° around its center.


rmgreen type

rmgreen is a chromatic noise reduction filter. It removes green noise in the current image. This filter is based on PixInsight's SCNR Average Neutral algorithm and it is the same filter used by HLVG plugin in Photoshop.

Type=1 stands for Average Neutral Protection, while type=2 stands for Maximum Neutral Protection.


save filename

Save current image to Fits headers MIPS-HI and MIPS-LO are added with values corresponding to the current viewing levels..


savebmp filename

Save current image under the form of a bitmap file with 8bits per channel: filename.bmp (BMP 24 bits). This function is like a screenshot of what you see with the levels updated. This is very usefull to share an image in the bitmap format.


savejpg filename [quality]

Save current image into a JPG file. You have the possibility to adjust the quality of the compression. A value 100 for quality parameter offers best fidelity while a low value increases the compression ratio. If no value is specified, it holds a value of 100. This command is very usefull to share an image in the jpeg format on the forums for example.


savepnm filename

Save current image under the form of a Netpbm file format with 16bits per channel. The extension of the output will be filename.ppm for RGB image and filename.pgm for gray-level image. More details about the Netpbm format at :


savetif filename

Save current image under the form of a uncompressed TIFF file with 16bits per channel.


savetif8 filename

Same command than savetif but the output file is saved in 8bits per channel.


split r g b

The command splits the color image into three distincts files (one for each color) and save them in r g and b file.



Returns global statistic of the current image. If a selection is made, the command returns global statistic within the selection.

threshlo, threshhi, thresh

These are threshold functions:

  • threshlo 40 replaces values below 40 with 40;
  • threshhi 1000 replaces values above 1000 with 1000;
  • thresh 40 1000 does both.


unsharp sigma multi

Applies to the working image an unsharp mask with sigma sigma and coefficient multi.


visu low high

Displays an image with low and high as the low and high threshold.


wavelet plan_number type

Computes the wavelet transform on plan_number plans using linear (type=1) or bspline (type=2) version of the 'a trous' algorithm. The result is stored in a file as a structure containing the planes, ready for weighted reconstruction with wrecons.


wrecons c1 c2 ... cn

Reconstructs to current image from the planes previously computed with waveletand weighted with coefficients c1, c2, ..., cn according to the number of planes used for wavelet transform