Siril
Siril: A powerful free desktop toolkit for astrophotography calibration, stacking and denoising. Ranked #16 of 29 in Photo Noise Reduction Software by our editors (6.7/10); pricing: Free plan; best for open-source astrophotography denoise pipelines.
At a glance
- Editor score6.7 / 10
- PricingFree plan
- Best forOpen-source astrophotography denoise pipelines
- Free planYes
- Paid fromFree
- AI denoisingYes
- Facts checked21 Oct 2026
Where it wins
- Calibrates RAW and FITS data with registration and stacking.
- Includes NL-Bayes, DA3D and SOS denoising algorithms.
- Supports scripts, Python extensions and specialist integrations.
Where it doesn't
- Its workflow is oriented toward astronomical imaging rather than general photos.
- AI denoising comes through documented third-party integrations.
- Runs as desktop software with community and documentation support.
Our verdict on Siril
Siril is an open-source desktop application for astrophotographers and scientific users who need to process astronomical image data locally. It calibrates RAW and FITS files, registers and stacks exposures with outlier rejection, and provides tools for histogram stretching, color calibration, deconvolution and denoising. Linux, Windows and macOS versions support solo, small-team and mid-market workflows built around astronomical imaging rather than general-purpose photo editing.
Its strongest differentiator is the depth of its astronomy pipeline. Dedicated denoisers include NL-Bayes, DA3D and SOS, while SER video and FITS-cube processing extend beyond still-image workflows. Command-line operation and sequential scripts support repeatable processing, and Python scripting adds filters, visualization tools and integrations. Sirilic, Starnet++, RC-Astro NoiseXTerminator and Python are documented integration points, giving users options for extending Siril within a broader astrophotography workflow. Astrometry and photometric analysis tools add measurement-oriented capabilities alongside image enhancement.
Siril is free to use under its open-source model, with processing performed on the desktop. The published feature set favors users comfortable with calibration, stacking and scripted workflows; onboarding is therefore better suited to technically inclined astrophotographers than to casual photo editors seeking a focused noise-reduction utility. Its core denoising documentation does not adopt neural-network denoising, while official Python-script documentation describes third-party AI denoise integrations. Choose Siril when RAW/FITS handling, stacking, automation and astronomy-specific analysis matter most. Choose a general photo denoiser instead if you need a simpler workflow centered on ordinary photographs or built-in neural denoising.
Your product? Our editors can test Siril in depth and publish a review, labelled as paid · from $149/mo →
Siril pricing
Siril fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| RAW file support | Yes |
| AI denoising | Yes |
| Batch processing | Yes |
| Plugin support | Yes |
| Desktop platforms | Both |
| Processing mode | Local |
| Deployment | Desktop |
| Platforms | Windows, macOS, Linux |
| Support | Community, Docs |
| Built for | Solo, Small business, Mid-market (editorial estimate) |
| Integrations | 4 integrations: Sirilic, Starnet++, RC-Astro NoiseXTerminator, Python See all → |
| Pricing | Free plan |
| Website | siril.org |
| Facts checked | 21 Oct 2026 |
Siril integrations
Siril lists 4 integrations on its own site.
- Sirilic
- Starnet++
- RC-Astro NoiseXTerminator
- Python
Alternatives to Siril
- Topaz PhotoAI denoise and broad retouching for editors working in desktop photo workflows.8.8
- Nik DfineA selective, profile-driven denoiser for established desktop editing workflows.8.6
- ON1 NoNoise AIA capable one-time AI denoiser with broad plugin support and desktop-only delivery.8.4
Used Siril? Be the first to review it
The editor score above is our own research. What this page doesn't have yet is a reader's view — what you used Siril for, what worked and what didn't. No stars are seeded and no review is paid for; an editor reads every one before it appears.
Write a reviewTwo minutes · verified accounts only · read by an editor before it appears
Featured on iTechGuides
Siril is listed in our Photo Noise Reduction Software directory. Add the badge to your site — it links back to this page.
<a href="https://www.itechguides.com/products/siril/"><img src="https://www.itechguides.com/best/badge/siril.svg" alt="Featured on iTechGuides" width="230" height="46"></a>
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update