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.

This RC1 focuses primarily on bug fixes and overall stability improvements. We have resolved numerous issues reported by the community following Beta 4, particularly concerning CFA image processing, Drizzle, and sequence handling.

To discover all the major 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.

Major fixes in RC1 #

CFA image processing and debayering #

• Critical fix for Bayer pattern interpretation after background extraction on CFA images (#1799)
• Fixed X-Trans sensor debayering following changes introduced in beta 4 (#1826)
• Fixed OIII extraction by changing the normalisation strategy between B and G pixels (#1805)

Drizzle and sequence handling #

• Fixed drizzle registration when compression is on (#1800)
• Fixed computing storage space after seqpplyreg to better account for max framing (#1802, #1843)
• Fixed global registration failing to add reference image to the aligned sequence (#1798)

Stability and robustness #

• Fixed crash in seqstarnet (#1814)
• Fixed seqpsf bug preventing astrometric registration in some circumstances (#1815)
• Fixed crash in clearstar command with Dynamic PSF window open when called from python (#1821)
• Fixed crash when using noise weights in stacking if overlap normalization was selected (#1816)
• Fixed processing thread / child process accounting in the “Stop” dialog (#1705)

File and sequence handling #

• Fixed issue where sequences would not load correctly if file extensions did not match the preferred FITS extension (#1796)
• Fixed issue with create_new_seq() where the seqname contained a dot (#1841)
• Fixed issue with sequence filename construction if com.pref.ext didn’t match the seq (#1796)
• Fixed using reference image position and updating WCS in Export Sequence (#1824)

Other critical fixes #

• Fixed unnecessary range clipping/scaling prior to RGB channel extraction (#1797)
• Fixed issue where curves tool preview could fail to disapply (#1801)
• Fixed PLTSOLVD keyword that was not correctly propagated (#1807)
• Fixed writing RA/DEC to star lists from a single findstar command (#1794)
• Fixed issue with RGB composition not always applying registration (!948)
• Fixed min/max stacking for (0,0) pixel (#1810)
• Fixed issue with deconvolution using RGB PSFs (#1829)
• Fixed some static analysis errors (!950)
• Fixed some issues with rescale and rgbblend clipping protection in asinh stretch (!950)
• Fixed incorrect variable substitution regex handling in Pixelmath
• Removed use of deprecated python method locale.getdefaultlocale() which will be removed in Python 3.15

Significant improvements in RC1 #

Performance optimizations #

• Enabled compiler optimizations by inlining many common data conversion functions (!942)
• Made ONNXHelper slightly more robust (!940)

Python scripts and API #

• Added prefix arg to SirilInterface.set_seq_frame_pixeldata() to make it easier to create new sequences
• SirilInterface.get_siril_selection() now works if an image or sequence is loaded, not only an image
• Added SirilInterface.save_image_to_file() method to save from python to FITS files without needing astropy (!955)
• Fixed issue where sirilpy.SirilInterface.confirm_messagebox() could hang Siril (#1832)
• Fixed issue where the locale fix previously added to sirilpy would fail if no English locale was available (siril-scripts:#67)

Image processing and stacking #

• Use descreening instead of subtraction to generate starnet starmask, for better integration with recomposition tool (!941)
• Starlink pre- and post-autostretch is unlinked for better star removal from images with very uneven channels (!952)
• Stacking with rejection: make sure pixels with non-null values but 0 weight are now discarded at rejection step (!953)

User interface and ergonomics #

• Support arbitrary script categories in the GtkTreeView in script preferences

Towards the stable release #

This RC1 very likely represents the final step before the publication of stable version 1.4.0. The focus on bug fixes and code stabilization demonstrates our commitment to delivering a robust and reliable final version.

If no major issues are discovered during testing of this release candidate, we will soon proceed with the publication of the stable Siril 1.4.0.

Important note for master branch users: Once the stable 1.4.0 version is released, development of Siril 1.5 will begin on the master branch. Users accustomed to using daily builds from master are advised to exercise caution during the early phases of version 1.5 development, as this period may be more unstable than usual. We recommend waiting a few weeks after the start of the 1.5 cycle before resuming daily use of the master branch.

What we want from you #

As with previous beta versions, we encourage all users to report any bugs encountered via the Siril GitLab site . For bugs encountered with scripts, it’s here .

Your feedback is essential to help us finalize stable version 1.4.0 under the best conditions. This testing phase is crucial: the more intensively you test this RC1, the higher quality the stable release will be.

Known bugs #

Before opening a new ticket, you can check here if they are already known and/or fixed. Their correction will occur with the release of the next version:

• List of known bugs