11 Best Astrophotography Processing Software in 2026
That does not necessarily mean you captured bad images. Most astrophotography data needs calibration, alignment, stacking and careful editing before its hidden detail becomes visible.
The difficult part is choosing the right software. PixInsight can handle almost every stage of deep-sky processing, but it demands time and patience. Siril offers an impressive collection of tools without charging anything. Programs such as AutoStakkert! and RegiStax are better suited to planets, while Lightroom makes more sense for a single Milky Way landscape.
There is no single best software for processing astrophotography in every situation. The right choice depends on what you photograph, how much experience you have and whether you want one complete program or a collection of smaller tools.
Best Astrophotography Processing Software: Quick Comparison
| Software | Best for | Platforms | Price |
|---|---|---|---|
| PixInsight | Advanced deep-sky processing | Windows, macOS, Linux | Paid |
| Siril | Best free all-in-one option | Windows, macOS, Linux | Free |
| Astro Pixel Processor | Mosaics and easier deep-sky processing | Windows, macOS, Linux | Paid |
| StarTools | Guided deep-sky post-processing | Windows, macOS, Linux | Paid |
| DeepSkyStacker | Simple deep-sky stacking | Windows | Free |
| AutoStakkert! | Planetary, lunar and solar stacking | Windows | Free for private use |
| RegiStax | Planetary sharpening | Windows | Free |
| Sequator | Milky Way and nightscape stacking | Windows | Free |
| Adobe Photoshop | Detailed finishing and colour work | Windows, macOS | Subscription |
| Adobe Lightroom | Milky Way and nightscape editing | Windows, macOS, mobile | Subscription |
| Affinity | Free layer-based photo editing | Windows, macOS | Free |
Prices and licensing terms can change, so check the developer’s website before downloading or purchasing a program.
1. PixInsight
PixInsight is the program many experienced deep-sky photographers eventually move toward. It was designed specifically for astronomical image processing, so its tools deal with problems that ordinary photo editors do not fully understand.
You can use it to calibrate light frames with darks, flats and bias frames, register stars, integrate exposures, remove gradients, calibrate colours, stretch faint data and reduce noise. It is also particularly strong for narrowband images and complex projects involving multiple filters.
Its flexibility is both its greatest strength and its biggest weakness. Opening PixInsight for the first time can feel like stepping into scientific software rather than a photo editor. Many tools use terms such as deconvolution, linear fitting and pixel math, and the interface does little to explain where a beginner should start.
The Weighted Batch Preprocessing script makes calibration and stacking more manageable, but producing a polished image still requires an understanding of the individual processes. Once you build a repeatable workflow, however, PixInsight gives you an enormous amount of control.
PixInsight is the best astrophotography processing software for serious deep-sky photographers who are prepared to learn it properly. It is probably unnecessary for someone who only photographs the Milky Way a few times each year.
A commercial licence currently costs €300 for customers outside the European Union, and a fully functional 45-day trial is available through the official PixInsight website.
Best for: Experienced deep-sky and narrowband photographers
Main drawback: Expensive and difficult to learn
2. Siril
Siril is the first program I would recommend to most beginners who want to process deep-sky images without buying software immediately.
It is not simply a free photo editor. Siril can handle calibration, registration, stacking, background extraction, colour calibration, stretching and several later processing steps. Built-in scripts can automate much of the journey from individual light and calibration frames to a usable stacked image.
The interface still takes time to understand. You need to learn why astrophotographers use darks and flats, what registration does and why an image initially looks almost black before stretching. The difference is that you can learn all of this without making a financial commitment.
Siril has also developed quickly. The current 1.4 series added substantial improvements to stacking, mosaics, scripting, astrometric alignment and image processing. Version 1.4.4 was released in June 2026, showing that the project remains actively maintained. You can find the current downloads and release information on the Siril website.
For a beginner using a DSLR, colour astronomy camera or smart telescope, Siril may be all the software needed to create a good finished image. More experienced users often combine it with GraXpert, Affinity or Photoshop for additional control near the end.
Best for: Beginners who want capable free astrophotography software
Main drawback: Its terminology and workflow can feel technical at first
3. Astro Pixel Processor
Astro Pixel Processor sits between Siril and PixInsight. It offers a complete deep-sky workflow but presents the calibration and stacking stages in a more guided order.
The numbered interface walks you through loading files, calibrating frames, analysing stars, registering images, normalising exposures and integrating the final stack. It is not the most modern-looking program, but its sequence is easier to follow than PixInsight’s collection of separate processes.
APP is especially useful when working with mosaics. Combining multiple panels of a large target can be difficult because every panel may have a slightly different background brightness or gradient. Astro Pixel Processor is good at registering those panels and blending them into a more consistent image.
Its post-processing tools are useful, although they do not offer the same depth as PixInsight. Some photographers therefore perform calibration, integration and mosaic creation in APP before completing the image in another editor.
Astro Pixel Processor works on Windows, macOS and Linux. A free 30-day trial is available, while its owner’s licence is currently listed at €165 before VAT on the official APP store.
Best for: Deep-sky mosaics and photographers who find PixInsight overwhelming
Main drawback: The interface is functional rather than intuitive
4. StarTools
StarTools takes a different approach to astrophotography post-processing. Instead of giving you a blank workspace and dozens of unrelated controls, it tracks how noise changes as you work through the image.
That approach affects tools such as stretching, deconvolution and noise reduction. The program tries to preserve useful signal while keeping a record of how earlier adjustments have affected the data.
StarTools is mainly a post-processing application. You will normally create a calibrated and stacked file in Siril, DeepSkyStacker or another stacking program before opening it in StarTools. Once the stack is loaded, its modules help with common jobs such as correcting gradients, developing faint detail, improving colour and reducing noise.
The workflow is more guided than PixInsight, although the terminology can still seem unusual. It works best when you follow the recommended order instead of treating it like Photoshop and jumping randomly between adjustments.
A StarTools licence currently costs 69 AUD. Its trial has no fixed time limit and includes the program’s features, but you cannot save the finished image until you purchase a licence. Current pricing and trial information are available on the StarTools website.
Best for: Deep-sky photographers who want structured post-processing
Main drawback: Requires a separate program for calibration and stacking
5. DeepSkyStacker
DeepSkyStacker, usually shortened to DSS, has helped generations of Windows users create their first stacked deep-sky image.
Its job is deliberately limited. You load light frames along with darks, flats and bias frames, ask the program to register the stars, and then combine the best exposures. Stacking increases the signal-to-noise ratio, making faint details easier to reveal later.
DSS supports several stacking and rejection methods, but it is not intended to be a complete editor. The image shown immediately after stacking often looks flat, grey or strangely coloured. That is normal. Save the result as a high-bit-depth TIFF and continue processing it in another program.
The simple workflow makes DeepSkyStacker approachable, although its settings can become confusing once you move beyond the defaults. It is also Windows-only, which makes Siril the more practical free choice for Mac and Linux users.
DeepSkyStacker remains a useful option if you want a dedicated program that performs preprocessing without surrounding you with advanced editing tools. It is available as freeware from the official DeepSkyStacker website.
Best for: Windows beginners who want straightforward deep-sky stacking
Main drawback: No complete post-processing workflow
6. AutoStakkert!
Deep-sky photographs and planetary videos need different processing methods. If you record thousands of short frames of Jupiter, Saturn, the Moon or the Sun, AutoStakkert! is one of the most useful programs you can install.
The software analyses the frames in a video, estimates their quality, aligns surface details and stacks the sharpest portions. This “lucky imaging” method helps reduce the effect of atmospheric turbulence. Instead of relying on one blurry frame, you combine the clearest moments from a recording.
AutoStakkert! is remarkably powerful, but its interface assumes that you already understand concepts such as alignment points, frame percentages and drizzle. Your first result may require a little experimentation. Once the stack is complete, it usually needs sharpening in RegiStax, waveSharp or another editor.
AutoStakkert! is native to Windows. The developer says it can run through Wine on macOS and Linux, but there are no plans for native versions. The current downloads are available from the AutoStakkert! website.
The software is freeware for private, non-commercial and educational use. Commercial users should read its licence terms carefully.
Best for: Stacking planetary, lunar and solar videos
Main drawback: Windows-only and not designed for final editing
7. RegiStax and waveSharp
RegiStax is an old program, but its wavelet sharpening tool is still familiar to planetary photographers.
After stacking a planetary video in AutoStakkert!, you can open the resulting image in RegiStax and use wavelet layers to reveal small details. Careful adjustments may bring out cloud bands on Jupiter, structure around a sunspot or fine texture across the lunar surface.
Wavelets can also ruin an image quickly. Pushing the sliders too far creates bright halos, harsh edges and a rough, crunchy appearance. The best results usually come from small adjustments combined with restrained noise control.
Development of RegiStax itself ended years ago. Its newer companion, waveSharp, continues the wavelet-sharpening side of the workflow and may be the better long-term option. Both are available through the official RegiStax and waveSharp website.
This is not the right software for processing galaxies or nebulae. It belongs in a planetary workflow, usually after AutoStakkert!.
Best for: Sharpening stacked images of planets, the Moon and the Sun
Main drawback: RegiStax is dated and easy to overuse
8. Sequator
Sequator is built for a problem that landscape astrophotographers know well: the stars move between exposures, but the ground does not.
When several nightscape images are stacked normally, aligning the stars can blur the foreground. Aligning the foreground causes trails in the sky. Sequator can identify the sky and foreground separately, align the stars and reduce noise while preserving a stationary landscape.
This makes it particularly useful for wide-angle Milky Way photography. It can also reduce light pollution, handle star trails and export a 16-bit TIFF for further editing.
The interface is relatively simple, and its automatic settings are helpful when you are learning. Even so, the sky mask should be checked carefully around trees, mountains and buildings. A poor mask can produce doubled edges or unnatural transitions near the horizon.
Sequator is free and currently supports Windows only. New camera RAW formats may need to be converted to DNG or TIFF before they can be loaded. Downloads and instructions are available on the Sequator website.
Best for: Milky Way landscapes with a visible foreground
Main drawback: No native Mac or Linux version
9. Adobe Photoshop
Photoshop was not built specifically for astronomy, yet it remains extremely useful during the final stages of an astrophotography workflow.
Layers and masks allow you to adjust a nebula without changing the stars, control colour in selected areas and blend exposures with different brightness levels. Curves, Camera Raw, selective colour and adjustment layers provide more creative control than many dedicated astronomy programs.
What Photoshop does not provide is a convenient scientific calibration workflow. It can align and combine layers, but using it to process hundreds of light, dark and flat frames is unnecessarily awkward. Deep-sky photographers normally stack in Siril, PixInsight, APP or DeepSkyStacker and move into Photoshop when the technical preprocessing is complete.
Photoshop is particularly appealing if you already use it for ordinary photography. The interface will feel more familiar than PixInsight, and the skills transfer easily to landscape and portrait editing.
Adobe’s Photography plan currently includes Photoshop, Lightroom and Lightroom Classic for $19.99 per month with an annual commitment in the United States. Regional prices may differ. Current details are listed on Adobe’s Photography plans page.
Best for: Colour work, masks, selective adjustments and final polishing
Main drawback: Subscription pricing and limited dedicated astronomy tools
10. Adobe Lightroom
Lightroom makes sense when your astrophotography starts with one RAW file rather than hundreds of telescope exposures.
For a Milky Way landscape, it provides an efficient place to adjust white balance, exposure, contrast, highlights, shadows and lens corrections. Its masking tools can separate the sky from the foreground, while noise reduction helps clean up high-ISO files.
It is also useful for organising large photo collections. If you return from a night shoot with dozens of compositions, Lightroom makes comparing, rating and editing them much easier than opening every image separately.
However, Lightroom is not a replacement for dedicated astrophotography stacking software. It cannot calibrate deep-sky frames with darks and flats, and it is not the right tool for aligning a planetary video. Think of it as a RAW editor and photo organiser for nightscapes rather than a complete astronomical processing program.
The standalone Lightroom plan is currently listed at $11.99 per month in the US and includes Lightroom Classic. It is also included with Photoshop in the broader Photography plan.
Best for: Editing and organising Milky Way or nightscape photographs
Main drawback: Not designed for astronomical calibration or stacking
11. Affinity
Affinity is one of the most interesting general photo editors for astrophotographers in 2026 because its professional editing toolkit is now available free.
It includes RAW development, layers, masks, batch processing, macros, HDR tools and detailed colour adjustments. Those features make it useful for cleaning up and finishing an image created in Siril, DeepSkyStacker or another dedicated astronomy program.
Affinity is especially attractive to photographers who want layer-based editing without an Adobe subscription. You can make selective changes, blend exposures and work with high-quality files while keeping the process more visual than it would be in PixInsight.
It still should not be confused with a complete scientific preprocessing program. For serious deep-sky work, use dedicated astrophotography stacking software first and bring the integrated TIFF into Affinity for the creative stage.
The new version of Affinity is advertised as free and includes its photo editing tools on Windows and macOS.
Best for: Free layer-based editing and final adjustments
Main drawback: Dedicated astro tools are less comprehensive than Siril or PixInsight
A Useful Extra: GraXpert
GraXpert is not a complete editor, but it solves one of the most frustrating astrophotography problems: uneven backgrounds.
Light pollution, moonlight, vignetting and imperfect flat-field correction can leave a bright gradient across an image. Simply darkening the background does not remove it properly and may hide faint parts of a nebula.
GraXpert models the unwanted background and subtracts it while trying to preserve the astronomical signal. It also offers noise-reduction tools and can fit neatly between stacking and final editing.
The program is free, open source and works as a standalone application. It pairs especially well with a low-cost workflow built around Siril and Affinity. You can learn more or download it from the GraXpert website.
Which Astrophotography Software Should You Choose?
The easiest way to choose is to start with the type of data you have.
For deep-sky photographs of galaxies, nebulae and star clusters, Siril is the strongest free starting point. It can take you from RAW exposures to a finished image without requiring several paid applications. PixInsight offers more control for advanced work, while Astro Pixel Processor is particularly attractive for mosaics.
Planetary photographers should begin with AutoStakkert! for frame selection and stacking. The finished stack can then be sharpened in waveSharp or RegiStax.
For wide-angle Milky Way landscapes, Sequator is an excellent free stacking tool on Windows. Lightroom, Photoshop or Affinity can handle the remaining colour and tonal adjustments.
If you only want one recommendation and do not yet know what you need, download Siril. Use it until you encounter a specific limitation. By that point, you will have a much better idea whether you need PixInsight’s control, APP’s mosaic tools or Photoshop’s flexible masks.
Stacking Software and Processing Software Are Not the Same
The terms are often used together, but they describe different stages.
Stacking software aligns multiple frames and combines them into one master image. This reduces random noise and makes faint signal easier to reveal. Calibration frames can also correct hot pixels, dust shadows, vignetting and sensor patterns.
Post-processing begins after the stack has been created. This stage includes stretching faint details, removing gradients, correcting colour, sharpening structures, controlling stars and reducing visible noise.
DeepSkyStacker and AutoStakkert! concentrate mainly on stacking. Photoshop, Lightroom and Affinity are primarily editors. Siril, PixInsight and Astro Pixel Processor cover much more of the complete workflow.
Understanding that difference prevents a common beginner mistake: opening one noisy RAW exposure in Photoshop and expecting it to contain the same detail as a properly calibrated stack.
Recommended Astrophotography Processing Workflows
You do not need to buy every program on this list. A short workflow that you understand will usually produce better results than a folder containing six complicated applications.
Free deep-sky workflow
Siril → GraXpert → Affinity
Siril handles calibration, registration and stacking. GraXpert corrects difficult gradients, and Affinity provides layers and masks for final adjustments.
Simple Windows deep-sky workflow
DeepSkyStacker → Affinity or Photoshop
This is a practical option if you want stacking and creative editing to remain separate.
Advanced deep-sky workflow
PixInsight → Photoshop
PixInsight handles the technical processing, while Photoshop provides flexible masks and final colour adjustments.
Planetary workflow
AutoStakkert! → waveSharp or RegiStax
AutoStakkert! selects and combines the clearest video frames. The second program sharpens the resulting image.
Milky Way landscape workflow
Sequator → Lightroom, Photoshop or Affinity
Sequator aligns and stacks the night sky, while the photo editor balances the sky and foreground.
Frequently Asked Questions
What is the best software for processing astrophotography?
PixInsight is one of the most complete choices for advanced deep-sky astrophotography. Siril is the better starting point for beginners because it is free and can handle calibration, stacking and post-processing. The best choice changes for planetary and Milky Way photography.
What is the best free astrophotography processing software?
Siril is the best all-round free option for deep-sky images. DeepSkyStacker is easier if you only need stacking on Windows, while AutoStakkert! is better for planetary videos. Sequator is designed for Milky Way landscapes.
Is Siril good enough for beginners?
Yes. Siril has a learning curve, but its scripts can automate much of the preprocessing workflow. It also gives beginners room to improve without forcing them to purchase another program immediately.
Is PixInsight better than Siril?
PixInsight provides a deeper collection of specialised tools and more control over advanced processing. Siril is free, easier to justify for a beginner and capable of producing excellent images. Buying PixInsight will not automatically improve a photograph if you have not learned calibration, stretching and colour correction.
Can Photoshop stack astrophotography images?
Photoshop can align layers and create certain types of image stacks, but it is not efficient for calibrating and integrating large deep-sky datasets. Dedicated software such as Siril, DeepSkyStacker, Astro Pixel Processor or PixInsight is better for that stage.
What software is best for planetary astrophotography?
AutoStakkert! is one of the best options for analysing and stacking planetary, lunar and solar video frames. The stacked image can then be sharpened with waveSharp or RegiStax.
What software should Mac users choose?
Siril, PixInsight and Astro Pixel Processor are suitable for deep-sky work on macOS. Photoshop, Lightroom and Affinity are available for general editing. DeepSkyStacker, Sequator and AutoStakkert! do not provide native Mac versions.
Final Thoughts
The best astrophotography software is not always the most expensive one. A beginner who understands Siril can produce a better image than someone clicking randomly through PixInsight.
Start with the program that matches your subject. Use Siril for deep-sky images, AutoStakkert! for planets or Sequator for a Milky Way landscape. Add a general editor only when you need more control over colour, masks and final presentation.
Processing becomes much less confusing once you stop searching for one application that does everything and build a small workflow around the photographs you actually take.
