Siril

About

Sun, 06 Sep 2020 10:13:55 +0000

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).

Contributors are welcome .

Programming language is C, with parts in C++. Main development is done with most recent versions of shared libraries on GNU/Linux.

FAQ

Sat, 19 Dec 2020 11:09:49 +0000

Usage questions #

I don’t have flats, how can I use scripts? #

Official scripts are made to process images in the best way, which assumes that you have dark, flat and flat-dark images. If you have different or less files, you will have to either modify the script (see below) or find one that has already fits your needs in the dedicated page or somewhere else.

Shop

Thu, 31 Mar 2022 15:28:49 +0000

The official Siril book #

Master Siril from A to Z with the official manual!

Discover the complete technical guide to Siril, written by the principal developer. This detailed manual takes you through every step of astronomical image processing, from the basics to the most advanced techniques.

Now available for pre-order at siril.us – €59, shipping included worldwide

Ideal for:

🔍 Search

Mon, 01 Jan 0001 00:00:00 +0000

Donate

Sun, 06 Sep 2020 11:09:49 +0000

Thank you for downloading Siril! 🎉

We work hard to provide you this awesome tool and if you'd like to help us out for our efforts please consider donating. We greatly appreciate any support!

🤫 Psst... Looking to go further with your astrophotography gear? Our friends at EOS for Astro offer professional camera de-filtering services (Canon, Nikon, Sony…) to unleash your sensor's full potential for deep-sky imaging.

Siril 1.4.3

Thu, 07 May 2026 00:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.3!

This maintenance release continues to build on the stability and scripting improvements introduced in 1.4.2, with a series of targeted bug fixes across the Python interface, background extraction, file handling, and image loading — as well as a handful of useful new capabilities for Python scripting workflows.

Siril Book – English Edition!

Wed, 22 Apr 2026 00:00:00 +0000

We are thrilled to announce that the English edition of the reference book on astrophotography and Siril is now available for pre-order and will ship from May 5, 2026! Published by Axilone – Astronomy, this 192-page richly illustrated book is the most comprehensive guide ever written on Siril (more info at siril.us ).

A French edition has been available since November 2025. Versions in Italian, German, and Spanish are also in preparation and will follow in the coming months.

Siril 1.4.2 Windows hot fix

Fri, 10 Apr 2026 00:00:00 +0000

Siril 1.4.2-HF1 #

This hot fix release is intended only for Windows users (the binaries are provided only for this OS). It addresses a bug that may affect you if your Windows profile uses wide chars, see ticket #1936 , in which case Siril could not save your preferences or download online catalogues. This was introduced by one of our dependencies which introduced this regression. This release is a simple rebuilt of 1.4.2 code with a newer version of this library.

Siril 1.4.2

Wed, 18 Feb 2026 00:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.2!

This maintenance release continues to refine Siril 1.4 with a focus on stability fixes, significant improvements to Python scripting — in particular GPU library management — and enhanced catalogue handling. It also introduces an experimental new Windows build for users hitting file count limitations.

A Brand-New Star Removal Script Comes to Siril - Zenith

Fri, 30 Jan 2026 00:00:00 +0000

We are very pleased to announce the release of a brand-new star removal script in Siril, based on an original artificial intelligence model, generously developed by SyQon specifically for the Siril community.

Unlike many existing approaches that rely on encoder–decoder architectures with successive resolution reduction and reconstruction stages, Zenith follows a fundamentally different design philosophy. The model operates largely at native image resolution, significantly reducing spatial information loss.

Instead of reconstructing details after aggressive compression, information is refined progressively, using local and global aggregation mechanisms designed to preserve fine structures and photometric consistency.

Siril 1.4.1

Mon, 05 Jan 2026 00:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.1!

This maintenance release addresses several important issues reported by the community following the release of Siril 1.4.0 stable in December 2025. Version 1.4.1 focuses on improving compilation flexibility, fixing Python scripting issues, and enhancing catalogue functionality.

Siril 1.4.0

Fri, 05 Dec 2025 00:00:00 +0000

Introduction #

We are immensely proud to announce the release of Siril 1.4.0 stable!

Siril 1.4.0 RC2

Thu, 20 Nov 2025 05:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.0 RC2 (Release Candidate 2), twelve days after RC1 released in early November . This second release candidate fixes several critical bugs identified by the community and very likely represents the final step before the stable release of Siril 1.4.0.

Siril 1.4.0 RC1

Sat, 08 Nov 2025 05:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.0 RC1 (Release Candidate 1), following Beta 4 released in late September . This release candidate marks a decisive step towards the stable release of Siril 1.4.0.

Siril 1.4.0 Beta 4

Sun, 28 Sep 2025 05:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.0 Beta 4, following Beta 3 released back in July . This new version likely represents the final beta before the stable release, as it integrates all the major features planned for Siril 1.4.0.

Siril 1.4.0 Beta 3

Fri, 11 Jul 2025 05:00:00 +0000

Introduction #

We are happy to announce the release of Siril 1.4.0 Beta 3, which follows Beta 2 published last month . This new version brings numerous critical bug fixes and significant improvements, particularly in Python script management and overall application stability.

Siril 1.4.0 Beta 2

Wed, 21 May 2025 05:00:00 +0000

Introduction #

We are pleased to announce the release of Siril 1.4.0 Beta 2, following Beta 1 released last month . This new version includes numerous bug fixes and significant improvements based on community feedback.

To discover all the major new features introduced in Siril 1.4.0, please refer to the Beta 1 release notes, which detail important advances in astrometry, alignment, color management, photometry, Python scripting, and much more.

Fixed bugs in beta2 #

Fixed option -weight= for stack command and add filtering criteria in HISTORY key of stacked image (#1545)
Fixed crash and slowness when refreshing the scripts list (#1548, #1574)
Fixed crash in Noise Reduction with Independent Channels option selected (#1567)
Fixed UI hang when manually refreshing scripts or SPCC (#1566)
Fixed incorrect behavior when using set_image_pixeldata to change the number of channels (#1570)
Fixed incorrect siril command return values (#1569)
Fixed crash in astrometric registration when the reference image could not be platesolved (#1557)
Fixed preventing max framing export in seqapplyreg with FITSEQ or SER (#1561)
Fixed obscode that was not exported in the AAVSO csv (#1577)
Removed graxpert_deconv from the command line (#1575)
Fixed SPCC failing to open files on Windows when the filepath contains non-ASCII characters (e.g., accented characters) (#1584)
Fixed parameter parsing in PixelMath (#1594)
Fixed bad font kerning on macOS (#1508)
Fixed crash on Windows language change (#1560)
Fixed incorrect option handling in denoise (#1599)
Fixed poor star detection when input sequence was in 16b and preferences set in 32b (#1614)
Fixed incorrect image size with latest cameras added to LibRaw, Siril now uses 202502 snapshot (#1565)
Fixed metadata filling problem in PixelMath using $T (#1605)
Fixed crash in Image Plate Solver (#1609)
Fixed python API SirilInterface::set_seq_frame_incl (#1617)
Fixed FWHM units when printing alignment results (#1616)
Fixed incorrect behavior when opening the git repositories if a git lock file was in place
Fixed failure in stacking if both feathering and image filtering were selected (#1629)

Improvements in beta2 #

Scripts can be opened in the editor directly from the Script Preferences treeview (#1556, !860)
Added a fork of tkfilebrowser to support improved script UI file selection on Linux (!864)
Implemented a better linear regression algorithm for SPCC (!853)
Python scripts are now sorted alphabetically (#1559)
Made crop and ROI selection CFA-aware (#1579)
Added an optional rate limit for smooth scroll zoom speed (#1576)
Added SirilInterface.create_new_seq() and SirilInterface.is_cli() in sirilpy (!867)
GraXpert “Use GPU” now defaults to False but is persistent (saved in config)
Added utility.ONNXHelper class in python module to make it easier to ensure the correct onnxruntime module is installed. (!874)
Added ability to calibrate images for debayering only, without Dark, Flat, or Bias files (#1619)
Simplified the scripts and SPCC repository checking and made it more robust and thread-safe (!872)
Improved visibility of whether the autostretch preview is linked or unlinked (!878)
Changed the default GHT and asinh settings to update faster.
Added returning a dict from SirilInterface.get_image_fits_header() and SirilInterface.get_seq_frame_header in sirilpy (!877)
Improved Quit behavior if there are unsaved script changes.
Improved feedback when the python context manager image_lock() reports an error.
Improved method of calling scripts from the editor to eliminate a script length restriction.
Added a GraXpert python script to replace the legacy C GraXpert interface (siril-scripts:!42)
Deprecated the legacy C interface of GraXpert which proved unreliable (#1620, #1611, #1573)

What we want from you #

As with Beta 1, we encourage all users to report any bugs encountered via the Siril gitlab site . For the script bugs this is here . Your feedback is essential to help us finalize the stable 1.4.0 release.

Siril 1.4.0 Beta 1

Sat, 26 Apr 2025 05:00:00 +0000

Introduction #

It’s nearly time! Siril 1.4.0 is feature complete and we have finished our pre-release testing. The next stage is the beta release, where we encourage testing from a much broader range of Siril users. The code runs well and can already be used as a “daily driver”, however the increased number of eyes on the code during the beta releases is important to help identify any weird corner cases that we just haven’t come across ourselves.

Siril 1.2.6

Wed, 22 Jan 2025 00:00:00 +0000

Siril 1.2.6 Release Notes #

We are happy to announce the release of Siril 1.2.6. Although Siril 1.2.5 was supposed to be the last update in the 1.2 series, a critical bug in the Windows version required us to release a new patch. This bug was introduced after a recent update of cfitsio which caused issues with widechar filenames that were not UTF-8 encoded.

This update mainly addresses this problem, ensuring that Siril works seamlessly with non-UTF-8 filenames on Windows. We appreciate your patience and feedback in helping us resolve this issue.

The Twelve Days of Siril

Tue, 24 Dec 2024 00:00:00 +0000

The Siril team wish you all a very happy Christmas. In the spirit of the season we are excited to present these twelve Christmas offerings which showcase the huge advances coming soon in Siril 1.4. We don’t have a release date just yet as there are (very) few remaining loose ends to tie up, but we look forward to announcing a beta release early in 2025. Don’t forget that we also need your help!

We need you!

Mon, 23 Dec 2024 00:00:00 +0000

We’re excited to announce that Siril 1.4 is on its way! While we don’t have a set release date yet, we wanted to share a sneak peek of some standout features and opportunities for the community to get involved.

SPCC #

One of the main highlights is the new SpectroPhotometry Color Calibration (SPCC) tool, which will allow users to perform highly precise color calibration. However, to maximize its potential, we need a comprehensive database containing sensor information (for both monochrome and color cameras) and filter data. That’s where you come in! We’re building an open and accessible database, and we invite the community to contribute.

Siril 1.2.5

Fri, 22 Nov 2024 02:00:00 +0000

Siril 1.2.5 Release Notes #

We are happy to announce the release of Siril 1.2.5, which could be the last maintenance update in the 1.2 series before the major 1.4 release. This version focuses on fixing various issues and improving stability across different platforms, particularly on macOS. While being a maintenance release, it brings important stability improvements that will benefit all users, especially our macOS community. These fixes were made possible thanks to our active user community who took the time to report issues and provide detailed feedback. This continuous interaction helps us make Siril more reliable with each release.

Siril at RCE 2024

Wed, 13 Nov 2024 00:00:00 +0000

We were delighted to participate in the Rencontres du Ciel et de l’Espace 2024 in Paris, at La Villette, an essential event organized by the French Astronomy Association (AFA). The event took place on November 9, 10, and 11, and our presentation was a great success: the room was packed, and unfortunately, not everyone could get in.

During the presentation, we had the opportunity to showcase the new features of Siril 1.4.0, which is not yet released. It was an amazing moment, shared with astronomy and imaging enthusiasts.

New Siril Publication in JOSS

Fri, 25 Oct 2024 00:00:00 +0000

We are thrilled to announce the publication of a peer-reviewed article on Siril in the Journal of Open Source Software (JOSS). This publication is a major milestone for us, as it validates the software’s development, usability, and impact in the open-source and astronomical imaging communities.

If Siril has been part of your work, we encourage you to cite it using the following reference:

C. Richard et al., Journal of Open Source Software, 2024, 9(102), 7242. DOI: 10.21105/joss.07242

Siril 1.2.4

Wed, 11 Sep 2024 02:00:00 +0000

Siril 1.2.4 Release Notes #

This release of Siril 1.2.4 continues the effort to stabilize the 1.2 series by addressing a number of bugs that were reported by our dedicated community of users. Although no new features have been introduced in this version, the program is now more robust and reliable.

List of fixed bugs (since 1.2.3):

Fixed CFA statistics (#1342)
Fixed calibration command bug disabling cosmetic correction (#1348)
Fixed calibration GUI not parsing correcting flat when using path parsing (#1348)
Fixed non-deterministic parallel subsky RBF (#1352)
Fixed incorrect deconvolution command arg setting (issue raised on pixls.us)
Fixed GHT and HT not reverting previews from other dialogs (#1356)
Fixed crash when saving image (#1353)
Fixed execute button in wavelets not reverting preview (#1362)
Fixed CLAHE crash on mono image (#1354)
Fixed crash while extracting Green channel on CFA FITSEQ (#1305)
Fixed inverted sequences on exporting to SER (#1361)
Fixed a bug with histogram hi / mid / lo entry callback behavior (!735)
Fixed free space disk computation on macOS (#1368)

Downloads #

Siril 1.2.4 is available for download on the most common platforms (Windows, macOS, GNU/Linux). You can download it from the download page.

Siril 1.2.3

Wed, 19 Jun 2024 00:00:00 +0000

July 29th, release udpate for macOS packages #

The first bug found has not been completely corrected, and many users have reported slowness. We therefore invite all macOS users to download the new package, revision 3, which bears the build number 11207.

July 2nd, release udpate for macOS packages #

A bug has been found in macOS versions preventing the use of multiple threads during calculations. Both packages have been updated to version 2 (build number 10977). We invite all our macOS users to download the new packages.

Siril 1.2.2

Fri, 14 Jun 2024 00:00:00 +0000

We’re delighted to announce that Siril 1.2.2 is now available. Many bugs have been fixed compared to version 1.2.1 released last year, and we hope that version 1.2.2 will be as stable as possible.

List of fixed bugs (since 1.2.1)

Removed background extraction samples after using it in script (#1265)
Fixed catalog parser problem with negative declination (less than 1°) (#1270)
Fixed weighting by number of stars during stacking if number of stars is the same accross the sequence (#1273)
Improved mouse pan and zoom control to enable one-handed operation (!638, fixes #1271)
Added an option to the LINK command in order to sort output by date (#1115)
Fixed pixel size set by astrometry using binning_update preference (#1254)
Fixed crash when querying stats on a CFA image with a selection smaller than a 2x2 square (#1286)
Fixed crash when saving compressed and croped images (#1287)
Disabled supernumerary use of openmp in demosaicing, which could lead to a crash (#1288)
Fixed ser orientation error (#1258, #1261)
Fixed crash during rejection stacking when using shift-registered sequence (#1294)
Fixed mouse scrollwheel scrolling too fast (#1151)
Fixed drag & drop in image display on macOS (#1310)
Fixed bug in rgradient (Larson Sekanina) filter (#1313)
Fixed bug in generalized hyperbolic stretches (#1314)
Fixed path parsing error with savetif (#1318)
Added handling of empty command pipe reads (closes #1277)

Downloads #

Siril 1.2.2 is distributed as usual for the three most common platforms (Windows, macOS, GNU/Linux). See the download page.

New ZWO Seestar script and tutorial

Fri, 29 Mar 2024 00:00:00 +0000

We are pleased to announce the release of a script and tutorial dedicated to Zwo’s new All-in-One telescope, Seestar.

The tutorial explains step-by-step how to use the script, and then how to process the stacked image. The proposed script has been designed to automatically pre-process the raw images recorded by the Seestar and give the best image, automatically.

We hope it will meet your expectations. To find out how, click here . The link to download the script is in the tutorial.

Siril 1.2.1

Fri, 26 Jan 2024 00:00:00 +0000

We are pleased to announce that Siril 1.2.1 is now available. Many bugs have been fixed compared to the 1.2.0 release last year, and we hope that version 1.2.1 will be as stable as possible.

List of known bugs

None for the moment, fingers crossed.

List of fixed bugs (since 1.2.0)

Fixed Anscombe VST noise reduction option for mono images
Fixed HEIF import (#1198)
Fixed Noise Reduction Anscombe VST bug with mono images (#1200)
Fixed problems with Fourier Transform planning > Estimate (#1199)
Fixed data initialisation bugs in copyfits() and RGB compositing tool
Fixed exported x-column for lightcurves when Julian date is not selected (#1220)
Fixed sampling tolerance for astrometry which was incorrectly read (#1231)
Allowed for RA/DEC to be sorted in PSF windows (#1214)
Added SET-TEMP as valid FITS header to be saved (#1215)
Added configurable color for background extraction sample and standard annotations (#1230)
Fixed argument parsing error in makepsf (!593)
Fixed light_curve and csv export from plot when some images were unselected from the sequence (#1169)
Added undo/redo when platesolving with astrometry.net (#1233)
Fixed crash in findstar when detecting stars close to the border (#1237)
Fixed using wcs info when using light_curve command (#1195)
Allowed moving file into workdir to be picked up for livestacking (#1223)
Fixed the way we check if there is enough space to use quick photometry (#1238)
Fixed bit depth evaluation for 8-bit images (#1244)
Fixed division by 0 in PixelMath (#1249)

Table of Contents #

Download #

Siril 1.2.1 is distributed for the 3 most common platforms (Windows, macOS, GNU / Linux). Check out the downloads page.

Siril 1.2.0

Fri, 15 Sep 2023 00:00:00 +0000

We are delighted to inform you that Siril 1.2.0 is now available. Many bugs have been corrected since the previous release candidate, making this new version ready to become the final version.

This version doesn’t bring anything new compared to version 1.2.0-rc1, but it does include a large number of bug fixes. In fact, as the list of users grew ever larger, so did the number of bug reports we received, enabling us to fix a large amount of issues. Many thanks to you all.

Siril 1.2.0-rc1

Thu, 01 Jun 2023 00:00:00 +0000

We are pleased to inform you that Siril 1.2.0rc1 is now available, only a few weeks after the release of beta1. Many bugs have been fixed since the previous beta, which makes this new version more stable and reliable.

However, we remind you that the release candidate version of the software is an intermediate stage of development that precedes the final version. It should be noted that a release candidate may contain bugs, unfinished features and stability issues. It is made available to users for feedback and extensive testing. Your contribution in reporting problems will help the developers to improve the final version of the software.

Siril and Telescope.Live Launch New Tutorial Series

Sun, 07 May 2023 00:00:00 +0000

We are excited to share that Telescope Live, the online platform dedicated to astrophotography and remote imaging, has created a new video tutorial series for Siril, available for free for anyone. The 6 videos, totaling 39 minutes, are specially targeted at beginners. They cover many operations required to transform a raw dataset into a beautifully processed image.

Telescope Live operates very high quality telescopes under the best skies of both hemispheres and provides a huge number of pictures in their archive, yet at an affordable price. They spent time learning to use Siril, creating scripts, and producing the video tutorials, making them available for free. The fact that this tutorial series is free and available to anyone is because they share the same mission with us: making astrophotography accessible to everyone.

Siril 1.2.0-beta2

Sun, 12 Mar 2023 00:00:00 +0000

We are pleased to inform you that Siril 1.2.0-beta2 is now available, only a few weeks after the release of beta1. Many bugs have been fixed since the previous beta, which makes this new version more stable and reliable.

However, we remind you that the beta version of a software is a first version of the software that is still under test and development. It is made available for feedback and further testing before the final version is released to the public. Beta versions may contain bugs or incomplete functionality, and are intended for testing purposes. Please check this page regularly for updates and status of any bugs found in this beta 2.

Siril 1.2.0-beta1

Fri, 24 Feb 2023 00:00:00 +0000

A little more than a year ago, we released version 1.0.0 of Siril. This version number, highly symbolic, symbolized the age of maturity of a software that we believe had become stable and powerful. Since then, many updates came to improve little by little this version 1.0 by fixing many bugs and by bringing small improvements. In parallel to the development of this so-called stable branch, we have continued to intensively develop new features, resulting in profound changes. These features are now part of this new release with the version number 1.2.0-beta1.

Bug Fix for MacOS Ventura users

Sat, 03 Dec 2022 00:00:00 +0000

MacOS Ventura is the thirteenth major version of macOS, released recently. Currently, Siril cannot be executed correctly on it because it is impossible to use the mouse on the application. This bug, which is very annoying, is caused by low-level changes in Ventura that affect GTK, the library that manages the graphical interface of Siril. And all applications using GTK3 are affected by this bug, namely GIMP v2.99, RawTherapee, Inkscape, Darktable and many others…

Siril 1.0.6

Tue, 18 Oct 2022 00:00:00 +0000

While version 1.0.5 could be the last available version of the 1.0 branch, it turns out that some annoying bugs have been reported and needed to be treated as a priority. Siril 1.0.6 is therefore made available for bug fixing purposes only. Indeed, the development of version 1.2.0 is in full swing and currently takes us a lot of time.

We also take the opportunity of the release of this version, on October 18th, to wish a happy birthday to Cécile who has had her hands in the code of 1.2.0 for several months already, in order to make available a future version which will be incredible.

Siril 1.0.5

Fri, 09 Sep 2022 01:00:00 +0000

Shortly after the release of version 1.0.4, last week, we are forced to make a fix and release Siril 1.0.5 much earlier than expected. Indeed, we found a bug introduced in the previous version when we had fixed a bug. Sometimes, errors compensate and don’t show up, but when you fix one, the other one shows up. This is exactly what happened here. This bug is critical and causes a shift of 1 pixel in x and y after a registration of images on which there was a meridian flip. We would like to warmly thank Kristopher Setnes for finding this bug and making sure it doesn’t live for long.

Siril 1.0.4

Fri, 02 Sep 2022 01:00:00 +0000

It’s back to school time, and with it, comes a new version of Siril: version 1.0.4. This is one of the last (if not the last) of the 1.0 branch. This version is mainly a stabilization version, but it still contains a small new feature in the tool introduced in the last update, the generalized hyperbolic transformation. For more information please read on.

Downloads #

Siril 1.0.4 is distributed for the 3 most common platforms (Windows, MacOS, GNU / Linux). Check out the downloads page.

Siril 1.0.3

Tue, 28 Jun 2022 01:00:00 +0000

Before the month of June comes to an end, we had to release a new version in order to keep the cruising rhythm started after the release of version 1.0.

Downloads #

Siril 1.0.3 is distributed for the 3 most common platforms (Windows, MacOS, GNU / Linux). Check out the downloads page.

But of course, as Siril is a free software, you can build from the sources, available through the installation page.

Siril 1.0.2

Mon, 16 May 2022 00:00:00 +0000

Keeping up on the fantastic pace of one release per month, we are pleased to announce the release of Siril 1.0.2. This is once again a stabilisation version and a continuation of 1.0.1. We recommend you update to benefit from the bug corrections and new features described in this page.

Downloads #

Siril 1.0.2 is distributed for the 3 most common platforms (Windows, MacOS, GNU / Linux). Check out the downloads page.

Siril 1.0.1

Wed, 06 Apr 2022 00:00:00 +0000

One month after the release of Siril 1.0.0 (first stable version), we are pleased to announce the release of Siril 1.0.1 which stabilizes this version even more. Indeed, although the development of the 1.2 branch is particularly active, we decided to maintain a 1.0 branch in order to provide users with a follow-up of this first stable version.

Downloads #

Siril 1.0.1 is distributed for the 3 most common platforms (Windows, MacOS, GNU / Linux). Check out the downloads page.

Siril 1.0.0

Wed, 09 Mar 2022 08:00:00 +0000

10 years have passed since branch 0.9 restarted the then-dropped development of Siril. So we are extremely proud, happy and thrilled to release Siril 1.0.0 for download. This version is the result of a period of hard work started in 2020 and we hope it opens the beginning of a new era. Today, Siril team consists of 3 devs, the historical duo working under GNU/Linux environment, while the last team member works under Microsoft Windows, which has helped a lot stabilizing Siril behavior for this OS.

Enough with dark flats

Wed, 15 Dec 2021 11:35:34 +0000

(…Or flat darks or whatever you call them)

More and more, we see the term master dark flat all over the forums. These are supposed to replace the biases that are usually used in the standard preprocessing of astronomical images. We read that the result is better using a dark flat (shot with the same exposure time as the flats) than with standard biases. But is this really the case? Why such a frenzy for a master image that no one was talking about not so long ago?

Siril 1.0.0-rc2

Wed, 08 Dec 2021 00:00:00 +0100

This version is a stabilization of the rc1 version, the new features are presented in detail here . We invite you to read this page carefully in order to know the implemented functions. However, we have made a short video explaining a bit how to use the improved plotting feature:

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Downloads #

Siril 1.0.0-rc2 is distributed for the 3 most common platforms (Windows, MacOS, GNU / Linux). See download .

Siril 1.0.0-rc1

Sat, 20 Nov 2021 00:00:00 +0000

This is the first release candidate of the 1.0.0 version. It comes with some new features and many bug fixes compared to the previous beta version (0.99.10.1), and contain all features that will be present in the final version. From now, we will focus on bug fixes in order to release as soon as possible the 1.0.0 version.

This version also marks the arrival in the development team of Cécile (alias Cissou8) who is the author of a large number of improvements and who works on Windows! Thanks also to Florian Bénédetti for his enormous work on continuous integration.

Siril 0.99.10.1

Wed, 23 Jun 2021 01:00:00 +0200

June 23rd, release udpate #

Due to some bug reports with 0.99.10 version, we’ve decided to release this patched version.

Fixed star detection with resolution < 1.0
Fixed interpolation issue in global registration
Fixed timestamp issue with glib < 2.66
New MAD clipping algorithm

The version #

This is the fourth beta of the upcoming version 1.0. It comes with some new features and many bug fixes compared to the previous beta version (0.99.8.1) and also compared to the stable version (0.9.12), and continues the big refactoring started with the 0.99 series.

Siril 0.99.8.1

Sat, 13 Feb 2021 08:30:00 +0000

February 13rd, release udpate #

Due to a crash with some FITS files of the 0.99.8 version (generally coming from ASIAIR system), a bug fix was quickly released under the 0.99.8.1 version. We encourage everyone to update their software, even if Siril says that everything is up to date.

The release #

This is the third beta version of the upcoming 1.0 version. It comes with many improvements and bug fixes over the second beta (0.99.6) and also some over the stable version (0.9.12), and continues the big refactoring started with the 0.99 series.

Siril 0.99.6 (1.0.0 beta2 testing)

Tue, 22 Sep 2020 20:50:00 +0000

One month after the release of the first beta version of Siril 1.0, which was largely adopted and praised by users, we are releasing a second beta version, with number 0.99.6. It fixes important issues that were found in the previous release, 0.99.4, thanks to the kind feedback of our community. It has already been tested by many users and should work in most cases. Remember this is a beta version, but we consider it already better than the previous stable version, the 0.9.12.

What’s new in Siril 0.99.4

Wed, 02 Sep 2020 11:04:30 +0000

Siril 0.99.4, available here , has introduced a lot of new features. In this post, we have listed the highlighted ones.

32-bit native #

The most important and especially the most awaited change is the switch to native 32-bit floating point for all calculations. The default FITS format is now of type TFLOAT. The files are therefore twice as large in size as before and the memory used is also twice as large. However, where one would have expected twice as long computation times, a lot of optimization work was done throughout the code. For comparison, on a machine with an I9 core, 32GB of DDR4 RAM (a good machine), a stack of 47 images takes 5min 24s with version 0.9.12 while only 2min01s are needed to stack 32bits images under 0.99.4. That makes Siril probably the fastest tool to process your astronomy images.

Siril 0.99.4 (1.0.0 beta testing)

Thu, 13 Aug 2020 19:31:02 +0000

We think it is time, time to release this new version for beta testing.

Since the last stable version, the 0.9.12, more that 1400 commits were pushed to our repository, more than 66 000 new lines of code were added. A lot of new developers helped us in optimization, new features and bug fixes. It is for sure our biggest improvement to the code of Siril.

This is why, unlike we used to do, we’ve decided to publish a beta version for the three most common platforms. This version, the 0.99.4 has been tested for some time by a few lucky users and should work in most cases. If you have issues with it or find bugs, we would be very grateful if you could contact us or report them to our bug system tracker .

Animation of comet Neowise

Thu, 30 Jul 2020 07:49:37 +0000

Comet NeoWise in the evening sky – above Brünstelkreuz mountain (1734m)

The author: Frank Stefani is a beginner in astrophotography (since 6 months),and also been a professional photographer and experienced visual-only astronomer for over 4 decades.

Bravo, I love this picture!

Source: https://frank-stefani.de/astronomy/C2020F3NeoWise/C2020F3-NeoWise-Abendhimmel.html

https://discuss.pixls.us/t/how-to-stack-frozen-tracked-neowise-over-moving-foreground/19462

Python to generate Siril script for cooled OSC

Mon, 17 Feb 2020 07:34:09 +0000

A big thank you to Cecile for sharing, maybe it will give you some ideas, so follow this link: https://discuss.pixls.us/t/python-to-generate-siril-script-for-cooled-osc/16461

Clear skies,

Laurent

An article from “Libre Graphics World” talks about Siril

Tue, 04 Feb 2020 18:00:46 +0000

Take time to read this new: Week recap from “Libre Graphics World” 🙂

Follow this link: http://libregraphicsworld.org/blog/entry/week-recap-3-february-2020

Introduction to Siril’s GUI

Mon, 27 Jan 2020 15:50:53 +0000

Here is a video in English that presents the new interface of Siril.

It will be followed by many others in order to present all the features of the Siril software.

Remember to subscribe to our youtube channel.

Siril joined Pixls.us, the largest free/open photography community

Fri, 24 Jan 2020 13:07:58 +0000

We are proud to announce that Siril has joined PIXLS.US , the largest Free/Open Source Photography community.

Like other softwares such as The Gimp, Darktable or RawTherapee we now have a forum at this address: https://discuss.pixls.us/c/software/siril

Thank you for asking your questions on this new forum.

Clear Skies,

Laurent

Siril is available on flathub

Thu, 23 Jan 2020 08:15:29 +0000

Command line instructions #

Install: #

Make sure to follow the setup guide before installing #

flatpak install flathub org.free_astro.siril

Run: #

flatpak run org.free_astro.siril

Siril 0.9.12 available on macOS

Wed, 18 Dec 2019 10:06:06 +0000

It is Christmas for all macOS users right now. Indeed, 0.9.12 version has been now released for this platform. You can then go to the Download section in order to get it right now.

Siril 0.9.12

Mon, 04 Nov 2019 10:25:19 +0000

We are glad and proud to announce the release of the new Siril version: 0.9.12. This version containing a lot of improvement is accessible through the download section.

For more information about the new features, please follow this link .

Siril’s use in physics

Tue, 22 Oct 2019 17:44:59 +0000

Siril is not only used by amateur astrophotographers, but also by physicists from a completely different field!

Source: https://doi.org/10.1016/j.radmeas.2019.106201

Siril 0.9.12 is now in RC1 version

Wed, 09 Oct 2019 05:10:49 +0000

The development of the new version of Siril continues, the version is now RC1….

This development version is available under Linux.

Siril 0.9.11 is available

Mon, 27 May 2019 09:39:31 +0000

We are glad and proud to announce the release of the new Siril version: 0.9.11. This version containing a lot of improvement is accessible through the download section.

For more information about the new features, please follow this link .

MacOS Bundle

Mon, 29 Apr 2019 08:14:34 +0000

Hello,

We are looking for a MacOS specialist who would be able to realize, or help us realize the MacOS Bundle.

You can contact us at the following address:

Thank you in advance for your help,

The Siril development team

Get 15 % off our T-shirts and other accessories

Tue, 12 Mar 2019 15:50:04 +0000

Help us promote your favorite free astronomy image processing software by wearing Siril’s colors.

Discover the T-shirt and other accessories shop for the United states / Canada, other countries.

M42 by Exaxe

Mon, 11 Feb 2019 16:34:25 +0000

Stephane Gonzales (Exaxe) shot M42 in deepksy lucky imaging. The result is so stunning that we want to share you the result.

Take a seat, make your comfortable and enjoy.

The English thread is on the Cloudy Night forum .

To watch the full resolution follow the link .

One of the features of the next version of Siril : photometric color calibration

Sun, 10 Feb 2019 17:53:13 +0000

Siril 0.9.10

Thu, 17 Jan 2019 18:48:42 +0000

Siril 0.9.10 has been released and brings its load of new features and improvements. It provides a new comet registration method, astrometry solving, previewing for processing functions, and new commands available for scripts. Windows support has been improved, in particular for special characters in file names. We also have moved to a gitlab source and issue control system to facilitate interaction with users and developers. See other news in the release notes(https://free-astro.org/index.php?title=Siril:0.9.10 ).

SiriL has moved to Gitlab

Mon, 26 Nov 2018 21:20:52 +0000

SiriL has moved to a new collaborative programming infrastructure hosted by Gitlab . The new URL is:

https://gitlab.com/free-astro/siril

On the end-user side, we also replaced our old bug submission form by the one from Gitlab.

Sirilic and Sirilot: Two very useful utilities for Siril

Thu, 15 Nov 2018 10:20:30 +0000

SIRILIC #

(Siril Image Converter) is a software for preparing acquisition files (raw, Offset, Flat and Dark) for processing with SiriL software.

It does three things:

Structuring the SiriL working directory into sub-folders
Convert Raw, Offset, Dark or Flat files into SiriL sequence
Automatically generate the SiriL script according to the files present and the options

SIRILOT #

The Sirilic version V0.36 provides an additional tool: Sirilot

It’s the contraction of “SiriL + Lot”. SiriLot is a siril extension that allows you to batch process multiple channel and sessions. Indeed, Sirilic is adapted to process only 1 layer but as soon as you wanted to process the 4 layers LRGB, you had to do 4 times the operation “Copy + script generation”. The author still wanted to keep Sirilic: so he created a second tool with a more batch-oriented graphical interface:

New OS X installer available

Thu, 16 Aug 2018 15:03:29 +0000

A new OS X installer, packaged by a Siril user, is now available for the 0.9.9 version. The great news of this package is that the set of DSLR scripts is now embeded as it was already done for the Windows version. Moreover, it is now possible for the user to uninstall the application very easily and properly from his computer.

Go to the download section in order to get it.

Over 500 users for Siril’s online courses

Sat, 04 Aug 2018 10:16:21 +0000

You are now over 500 to use online courses.

😉

We are looking for volunteer translators

Sat, 14 Jul 2018 16:48:23 +0000

In order to offer you the best, we are looking for volunteer translators.

For the software: #

No programming experience is required. See the translation instructions page for software translation.

In any case, check the status of your language translation with cyril (at free-astro.org) if you want to help.

For the documentation and for the online courses: #

Send an email to the following address : contact(at siril.org).

Starts SIRIL pre-processing from KSTARS / INDI / EKOS

Sat, 07 Jul 2018 12:17:11 +0000

You may want to use Siril scripts to automatically pre-process your images at the end of the nightly sequence with KSTARS / INDI / EKOS. Or, you also may want to download the pre-processed, registered and stacked file and not all the RAW files in the case of a remote control observatory ?

Below is described the detailed procedure that was established after an exchange with Jasem, the main developer of EKOS :

The new version 0.9.40 of CCDciel includes scripts for Siril.

Mon, 02 Jul 2018 17:56:02 +0000

It is possible to use scripts to pre-process the new images automatically for example at the end of the nightly sequence.

You can now have your pre-processed files ready and immediately start the interesting part of the process. 😉

There is standard script you can use directly or if you have very specific needs you can modify them to make your own.
See here: https://www.ap-i.net/ccdciel/en/documentation/image_preprocessing

400 users of online courses

Sun, 01 Jul 2018 06:43:45 +0000

This morning you are 400 to use this free service: https://siril.linux-astro.fr/

Nearly 3 new users every day and this in a constant way since the opening of the service in January.

A big thank you to all

What’s new in Siril 0.9.9

Tue, 26 Jun 2018 13:25:48 +0000

This release contains some new features as well as some bug fixes: #

Major update of the command line, with completion and documentation in the GUI, enhanced scripting capability by running commands from a file and also allowing it to be run with no X11 server running with the -s command line option
Added commands to stack and register a sequence
Image statistics, including auto-stretch parameters and stacking normalization, are now cached in the seq file for better performance
Global star registration now runs in parallel
Workflow improvement by adding demosaicing as last part of the preprocessing
Added a filtering method for stacking based on star roundness
Added an option to normalize stacked images to 16-bit with average rejection algorithm
All GUI save functions are now done in another thread
Improved histogram transformation GUI
Improved support of various FITS pixel formats
Preserve known FITS keywords in the stacked image by average method
Added native open and save dialogues for Windows users
Various Windows bug fixes in SER handling
Fixed wrong handling of scale variations in Drizzle case
Fixed 8-bit images auto-stretch display
Fixed BMP support
Fixed issues in PNG and TIFF 8-bit export
Fixed the “About” OS X menu

SIRIL 0.9.9

Tue, 26 Jun 2018 13:24:23 +0000

This release is the ninth stability release for the 0.9 branch. Its SVN revision is 2403. It also has an SVN tag: 0.9.9. Stability updates and minor improvements occur in the dedicated 0.9 branch. This is the second version officially supported on Windows, and it even includes developments that were specially made for Windows. But please keep in mind that Siril is developed without Windows and that we rely on Windows users to test and give us feedback about integration or porting problems.

History

Tue, 26 Jun 2018 13:22:35 +0000

June 7, 2018
- The new 0.9.9 version has been released, with bug fixes, and new script feature.

February 19, 2018
- A patch of the 0.9.8 version has been released: 0.9.8.3.

January 31, 2018
- The new 0.9.8 version has been released, with bug fixes, improvements on lucky imaging and Windows integration.

December 4, 2017
- A new 0.9.8 version is progressing well and will particularly help people working on deep-sky lucky imaging.
- We have also started working on features for the next major version of Siril, version 1.0. The first development, started at the beginning of the year, aims to greatly speed up the display of images and the rendering effects and this looks very promising. Other major developments will be the use of a better precision, floating point, internal image format that will give better results with some algorithms, the parallelisation of preprocessing and the creation of a high quality registration and stacking method for planetary images. It will still take a lot of time, but that will be a fully featured and fast version of Siril. Current 0.9.x versions are stable and already provide great results for deep-sky image processing.

September 21, 2017
- New release 0.9.7. Click here for past releases. Siril is now available on Windows as a beta version!

June 20, 2017
- New release 0.9.6. Click here for past releases.

November 28, 2016
- New release 0.9.5. Click here for past releases. Development of major improvements such as native 32 bit images and GEGL rendering has started.

October 8, 2016
- A new team member has given a huge effort to bring you a fantastic new multi-language documentation, both browsable and in PDF.

August 17, 2016
- New release 0.9.4. Click here for past releases.

October 28, 2015
- First stable version available: 0.9.0. Stability updates and minor improvements will occur in the dedicated 0.9 branch.

June 10, 2015
- New registration method available! It is now possible to register images with an automatic global star detection tool. The algorithm takes into account the translation and the rotation.

April 13, 2015
- We have been working hard on accelerating stacking algorithms on multi-core CPUs, giving SER a better support and we are also working on the two main lacks of Siril: taking into account rotation and multi-point in registration, for better deep-sky and planetary registrations. These works are in progress, and will take some weeks to complete.

Privacy Policy

Tue, 26 Jun 2018 11:25:06 +0000

Who we are #

Our website address is: https://www.siril.org .

What personal data we collect and why we collect it #

Comments #

When visitors leave comments on the site we collect the data shown in the comments form, and also the visitor’s IP address and browser user agent string to help spam detection.

An anonymized string created from your email address (also called a hash) may be provided to the Gravatar service to see if you are using it. The Gravatar service privacy policy is available here: https://automattic.com/privacy/ . After approval of your comment, your profile picture is visible to the public in the context of your comment.

Advanced Siril scripting with bash or DOS

Mon, 01 Jan 0001 00:00:00 +0000

For fans of the command line, Siril allows you to integrate its scripts (a simple suite of Siril commands) into shell scripts (bash or dos) which are much more powerful and allow the management of variables. We will see in this tutorial how to create such scripts on a UNIX type platform as well as on Microsoft Windows. The first example we are going to present consists of simply resampling a 2x2 bin image into a 1x1 bin, multiplying its size by two with the siril resample command. A more complex example afterwards shows how to apply commands that are only available to single images to all the images of a sequence.

Automated Star Reduction Script

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial will show you how to install and use a Python script that automates your star reduction workflow within Siril. With this script, you can streamline the process of reducing the size of your stars in your astrophotography images and get stunning results in seconds!

Attention: The script requires Siril 1.4.0-beta1 or newer, and StarNet++ CLI installed and configured within Siril. The script also only supports FITS format images, and the image must be in a non-linear (stretched) state.

Automating with pySiril

Mon, 01 Jan 0001 00:00:00 +0000

pySiril is a Python package extending scripting capabilities, present natively in Siril. It is intended for users already familiar with scripts looking for an alternative to using complex shell or bat (on Windows).

With pySiril, you can:

write conditions and loops (if, else, for…)
easily write your own functions
get values returned by some of Siril functions such as stat, bg, cdg, bgnoise…

This library works for the 3 main OS, Linux, Windows and MacOS.

Cosmic hide-and-seek (chasing invisible asteroids)

Mon, 01 Jan 0001 00:00:00 +0000

Since Siril 1.4, new features have been introduced that make it easier finding invisible solar system objects in your images.
It is in a sense similar to the tutorial on comet stacking, except in the present case, we will use astrometry to find the objects of interest. This tutorial will take you through the steps to reveal them through stacking.

Preparing the sequence #

The sequence used to illustrate this tutorial was originally shot to capture the famous comet 67P/Churyumov–Gerasimenko , landing site to the ESA Rosetta mission.

Debugging Python scripts

Mon, 01 Jan 0001 00:00:00 +0000

Since version 1.4, Siril embarks a Python machine to write advanced scripts . This tutorial shows how to debug Python scripts you may write using an IDE.
This is in no way a tutorial to learn how to write in Python. We also assume you have a good working knowledge of Siril.

This tutorial is written using VSCode .
You can of course replicate this using another IDE.

Prerequisites #

Before jumping in this tutorial, you will of course need to have:

Discovering PixelMath

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial aims to introduce a tool for doing math with images: PixelMath. This tool meets users’ needs to manipulate images during more or less complex operations, as if they were manipulating mathematical variables.

A few reminders about image files #

The images we use in astrophotography can be:

First steps -- pre-processing with scripts

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial explores your first steps with Siril and its scripting capability. Siril comes with a few basic scripts. They allow you to preprocess your images in one click!

1. Create the folders to hold your image types. #

Create the following 4 directories named as:

biases
darks
flats
lights

2. Put your RAW images in the directories created in the previous step. #

Attention: don’t mix other files, even JPEG (or other formats), with your RAW files: Siril will take all the files inside the directories as input files for processing.

Full image processing (pre-processed with scripts)

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial explains step-by-step how to process raw deep-sky images using, at first, the automatic processing capabilities of Siril scripts up to the stacking of the images, then the image improvement features of Siril to produce a final image for Web publication for example. It was made with version 0.99.8.1, the current stable version in February 2021 (download ). The pictures show how to do it with Microsoft Windows, but the specific parts for this operating system are about copying files, so it should be easy to adapt to your operating system. Other scripts, not provided with the installer, can be found here .

Generalized Hyperbolic Stretch (GHS) Transformations

Mon, 01 Jan 0001 00:00:00 +0000

After integrating your data, stretching is essential to raise your image from the darkness and apply the contrast needed to reveal details. While Siril has simpler stretching tools, GHS provides the greatest freedom to reveal and highlight exactly what you want to communicate in any astronomical image.

How the GHS Parameters (sliders) change the Image and its Histogram #

The understanding comes most easily if you follow along by loading up an image you have completed yourself, or any already stretched image that you can read into Siril. It doesn’t have to be monochrome, but it does make it easier to follow the histogram changes. It doesn’t have to be starless or even an astronomical image - but it should contain at least some mid-level brightness. Here is my image, which represents a processed luminance channel from NGC2264 - the Christmas Tree Cluster (except, of course, without the star cluster itself).

Image Analysis

Mon, 01 Jan 0001 00:00:00 +0000

In this tutorial, we will analyze an image thanks to its stars. What does FWHM mean? Why is it a good measure of the quality of your picture?

Dynamic PSF tool #

Dynamic PSF has been present for quite a while in Siril. It can very be useful in many occasions, like global star registration. But a vast majority of users do not know how to use it.

Dynamic PSF window when star detection has been activated.

Manual pre-processing

Mon, 01 Jan 0001 00:00:00 +0000

Introduction #

In this tutorial, we will study the pre-processing process of an astro image taken with a digital camera (DSLR), but the processing of images from astronomical cameras is almost identical. Of course, Siril comes with scripts that perform this process automatically. However, in a number of cases, you will need to perform manual processing:

You want to understand what the scripts do: the best way is to do manual pre-processing!
You want to refine the pre-processing: scripts use default values that can be optimized
Your images contain gradients that are difficult to remove during processing. It is very interesting to remove them on raw images: the gradient is simpler and easier to eliminate.
You’re missing flats: of course, this is formally discouraged, but photography sessions don’t always go as planned!
And many other reasons… that belong to you :-)

Files used #

For this tutorial, we will assume that you have images of the object, biases, flats, and darks.

Mosaics

Mon, 01 Jan 0001 00:00:00 +0000

Since Siril 1.4, the new astrometric alignment method enables to create mosaics. This feature can be used for different use cases, whether you need to align frames with little overlap, frames shot with different setups (so different field of view and sampling) and so on. In this tutorial, we will address the two main use cases, that are:

In any case, please remember that processing mosaics is quite memory intensive because both cases deal with either large images (that need to fit in memory) or a large number of images. So more than ever, we recommend having plenty of RAM and images stored on a SSD.

Photometry

Mon, 01 Jan 0001 00:00:00 +0000

In this tutorial, we will explore the capabilities of Siril to perform photometric processing to display a light curve of a variable star. And in this example, the variability of the star comes from a transit of an exoplanet.

EPIC-211089792 b, an exoplanet in Taurus, discovered in 2016 #

Plate solving #

Courtesy of Gerard Arlic, one of the co-discoverers of EPIC-211089792 b under the direction of the astrophysicist A. Santerne, I have in my hands a set of 111 images containing a transit of the planet, a hot Jupiter, in front of the star WASP-152. These images are excellent as an example and represent the best of the pro-am collaboration. The scientific paper of its discovery can be found here .

The WASP-152 sequence loaded in Siril

Processing ZWO Seestar images

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial explores the pre-processing and processing of images obtained from ZWO Seestar. Pre-processing will be carried out using a dedicated script.

Preprocessing #

1. Download the script to preprocess your images #

We’ve created a script tailored to the pre-processing of your seestar. This means that this script expects to have several images which it will stack. Starting from version 1.4.0, Siril allows you to retrieve new scripts, developed by trusted third-party developers and hosted by the Siril team, via the Scripts tab in preferences. Caution however!! If you were already using this script previously, we recommend removing it first. Indeed, by installing the new one you would have the same script twice in the menu. To access preferences, simply click on the Hamburger menu, at the top right, in the form of 3 horizontal lines and choose Preferences.

Removing gradients

Mon, 01 Jan 0001 00:00:00 +0000

In this tutorial, suitable for all levels, we will discuss the processing of gradients present in astronomical images. Indeed, even when the images are taken under a Chilean sky, and this is the case for the image that we will be using to illustrate the technique, they can be degraded by a light gradient whose origin may vary.

RGB composition

Mon, 01 Jan 0001 00:00:00 +0000

Whether they come from a monochrome camera or a color camera with dual-band filters, creating a color image from a set of monochrome stacks is always a challenge. Many combinations are possible and there are specificities in the processing of each of them. In this tutorial we will go over the basics and discover the tools that Siril provides to make any color composition you like.

Signal to noise ratio

Mon, 01 Jan 0001 00:00:00 +0000

Signal and Noise #

We took several long exposure frames and stacked them to reduce noise in our Deep Space images. We do long exposures because we want to get more photons, because we want to increase our signal. We stack frames not to add their light, but to average their noise.

When we detect light, the number of photons we detect is not constant for a fixed level of brightness. They fluctuate randomly around the real value. We call this fluctuation shot noise. It is important to note that this noise is not introduced by the equipment. This shot noise is proportional to the square root of the signal, so higher signal level has more shot noise than lower levels.

Siril Man Page

Mon, 01 Jan 0001 00:00:00 +0000

Name #

   siril - image processing tool for astronomy and others

Synopsis #

   Siril GUI
    siril [options] [file]             Start Siril.

   Siril CLI
    siril-cli  [-i  conf_file]  [-f]  [-v]  [-c]  [-h]  [-p]  [-d  working_directory]  
   [-s  script_file] [-r input_pipe_path] [-w output_pipe_path] [im‐
   age_file_to_open]

Description #

Siril is an image processing tool specially tailored for noise reduction and improving the signal/noise ratio of an image from multiple captures, as required in astronomy. Siril can align, stack and enhance pictures from various file formats, even image sequences (movies and SER files). It makes use of OpenMP, supports all the cameras supported by libraw, and carries out its calculations in a high precision 32-bit floating point engine.

Starnet++ integration

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial aims to showcase use of the Starnet++ integration. This tool meets the needs of users to be able to manipulate images from Starnet++ with Siril, including Pixel Math, the Star Recombination Tool and the Synthetic Star Tools.

Siril Integration #

The integrated interface in Siril has no additional dependencies beyond requiring that Siril is compiled with libtiff support (this is the default, and if you are using packages your distribution will almost certainly have built it this way) and a working installation of Starnet++. Both v1 and v2 are supported.

Synthetic biases

Mon, 01 Jan 0001 00:00:00 +0000

In this tutorial we will see how to use synthetic offsets to calibrate flats and how to determine their level. I will use the terms bias or offset indifferently.

Why (and when) can I use a synthetic offset? #

The main objective of subtracting the masterbias from the flats is to set their zero value so that when dividing the lights corrected by the masterdark, their curvatures are matched, as explained in appendix . This is not about trying to remove readout noise (subtracting a masterframe never removes noise, it removes a signal while adding some noise). And in the particular case of flats, this is neither about removing other level variations, unless your sensor has:

Synthetic Stars

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial aims to explain the star synthesis tools available in Siril. This feature helps improve the profiles of stars in Siril.

Astrometry and Star Synthesis #

Siril has powerful astrometry tools that can detect stars in images and model them with various parameters including peak luminance, full width at half maximum, surrounding background level. Siril models stars as Gaussian profiles.

Working with Comets

Mon, 01 Jan 0001 00:00:00 +0000

This tutorial aims at addressing a periodically recurring topic, which is the processing of comet images. It will show you how to make still images, aligned on stars and/or the comet itself, simple animations or more complex animations using superstacking. All of this with photometric calibration applied to all the images so that the colours are accurately balanced.

Still images #

We will start this tutorial with a sequence of calibrated lights. If you need to learn how to do this, you can refer to the manual preprocessing tutorial or the script preprocessing tutorial. Unless you have changed the defaults, the sequence should be named pp_light_.seq. If need be, you could also proceed with per-sub background extraction on your sequence before starting this tutorial, in which case, you would be using a sequence named bkg_pp_light_.seq.