Siril
Copyright © 2012-2023, Team free-astro
<https://free-astro.org/index.php/Siril>
<https://www.siril.org>
Summary
Siril is an astronomical image processing tool.
It is specially tailored for noise reduction and improving the signal/noise
ratio of an image from multiple captures, as required in astronomy.
Siril can align automatically or manually, stack and enhance pictures from various file formats,
even image sequence files (films and SER files).
It works well with limited system resources, like in embedded platforms, but is
also very fast when run on more powerful computers.
Contributors are welcome. Programming language is C, with parts in C++.
Main development is done with most recent versions of libraries.
If you use Siril in your work, please cite this software using the following information:
C. Richard et al., Journal of Open Source Software, 2024, 9(102), 7242. DOI:
.
Requirements
For compilation, these tools are needed in addition to the base development packages:
Then, mandatory build dependencies:
- glib-2.0 (>= 2.56.0) Glib Convenience Library
- lcms2 for color space management
- cfitsio for FITS image read and write
- wcslib (>=7.12) to handle astrometric data
- fftw3 for Fourier transforms
- GSL (The GNU Scientific Library) for PSF implementation, histograms and
background extraction
- A C++ compiler for opencv code and avi exporter
- libopencv for various image transformation algorithms (>= 4.4, 4.2 is
possible without some shift-only registration)
- yyjson, (>= 0.10.0) for Siril update check, spectrophotometry
color calibration and metadata output
GUI libraries are optional: most users will require them so they are enabled
by default, but can be disabled if you only wish to build the headless siril-cli:
- GTK 4, (>= 4.12) as GUI toolkit
- gtksourceview5 to provide context highlighting in the script editor
Siril works internally with FITS files, but other file formats can be used as
input and converted using the conversion tab of the control window. Some file
formats are handled internally, like BMP, PPM and SER, some require external
libraries listed below. Libraries need to be present at compilation time, or
their support won't be included.
- libcurl for web access
- exiv2 to get thumbnails from files
- libraw for DSLR RAW files import
- libffms2 for films import (any format supported by ffmpeg)
- libtiff (>= 4) for TIFF format support
- libXISF (>=0.2.7) and zstd for XISF format support
- libjpeg or compatible libraries like libjpeg-turbo for JPEG format support
- libjxl for JPEG XL format support
- libheif for HEIF format files import
- libpng (>= 1.6) for PNG format support
- libavformat, libavutil (>= 55.20), libavcodec, libswscale and libswresample for avi export (usually provided by ffmpeg)
- libgit2 for git integration to sync with the official siril-scripts repository
- criterion for unit testing with meson (development)
All these libraries and programs are available in most Linux distributions and
free systems, maybe with the exception of ffms2 that is not as popular as the
others and may need to be compiled.
At runtime, you need a functional Python installation (>=3.9) including the
python3-venv and python3-pip modules, as well as python3-tk to support scripts with
GUIs. If you are using a prebuilt Siril package these will be included, but if you
are compiling from source you need to ensure these are available by installing the
appropriate packages for your operating system.
Scripting
Siril accepts commands from the graphical command line, from scripts as a file
that contains a sequence of commands, or from a named pipe. The list of
supported commands is documented
here. We recommend to use
the siril-cli binary for that as no X-server is needed.
Some general purpose scripts have been made by the developers and some power
users, and are provided with the source code and some installers. When they are
in some default directories or in the directories defined by the user in the
settings, scripts appear in a top-menu of the main window. See this
page for more
information about scripts and a list of scripts ready for use.
The named pipe is only enabled when using Siril in a non-graphical mode and when
the -p argument is passed to the program on the command line.
Download binaries
We maintain binary packages of the latest stable version of Siril. A full list
of all releases is available on
free-astro as well as
Siril's website. The available packages per
relesae might differ.
Download source
You can get Siril's source code from the release archives on the webpage or
fetch the latest version from our repository on
GitLab:
git clone --recurse-submodules https://gitlab.com/free-astro/siril.git
Building Siril for GNU/Linux
Siril uses the Meson build system. Run the following commands:
# adjust the prefix to wherever you want to install Siril
meson setup --prefix /usr/local --buildtype release _build
ninja -C _build
ninja -C _build install
To update your build/installation, run the following commands:
git pull
git submodule update
ninja -C _build install
To uninstall Siril, run the following command:
ninja -C _build uninstall
Using meson to build siril requires all optional dependencies to be available or explicitly
disabled on the meson command line adding -Dexiv2=false for example. The autotools way
still only enables dependencies that are found and is available using autogen.sh.
Building Siril for macOS
The official JHBuild-based build scripts are available in the
siril_macos repository.
Alternatively, you can install Siril via Homebrew. Please
note that this is not maintained by Siril developers.
brew install siril
Building Siril for Windows
The build process using msys2 is documented
here.
Translation instructions for Siril
If you're interested in contributing to the translation of the application and documentation,
we encourage you to use Weblate. Weblate is a
powerful web-based translation tool that allows for easy collaboration and efficient
translation workflow.
Notes on Siril FITS image format
Flexible Image Transport System (FITS) is an open
standard defining a digital file format useful for storage, transmission and processing
of scientific and other images.
FITS is the most commonly used digital file format in astronomy.
Since FITS is a container and doesn't specify the order and size of data, it's
useful to fix it at some point. Currently, Siril uses 32-bit floating point per
channel values (TFLOAT), and images are stored channel after channel on a
bottom-to-top, left-to-right order. The convention chosen is the same as professional
tools, like ds9 (Harvard Smithsonian Center for Astrophysics) and fv
(FITS viewer from NASA) that store images bottom-up too. More details are
described here.
All files imported and converted in Siril or files exported by Siril are in this
FITS format, except sequence files like SER and films, which are read from the
file and converted on-the-fly. Films should be converted to SER now to process
them, many parallel operations are unsupported on them.
Notes on image sequence files
Siril makes a strong case for the use SER sequences against the generic film
containers that are not well suited for astronomy data and that may not be read
the same way by different players. Siril can convert any film format supported
by FFMS2 (probably all ffmpeg formats, which is a lot) to SER, and even any
image sequence to SER.
Siril supports SER v3. See this page for more details.
Useful links
License
GPL-3.0-or-later
