TLDR
PixInsight is the gold standard for serious astrophotography, while free alternatives like Siril and GIMP work well for budget-conscious imagers.
Choose PixInsight for professional-grade deep-sky processing, Siril or Autostakkert for free stacking workflows, and Photoshop or Affinity Photo for advanced retouching.
Astrophotography requires specialized image processing to bring out detail from raw celestial data. This guide compares tools ranging from dedicated astronomical software to general-purpose editors, helping you choose based on your workflow and budget.
Whether you're stacking planetary images, processing deep-sky data, or creating star trails, the right software makes a significant difference in final image quality.
Each tool offers different strengths: some excel at image stacking and calibration, others at detailed post-processing and color correction.
best software for astrophotography processing Tools compared
Filter by what you care about. Every tool stays on the page.
| Tool | Price | Astronomical Focus | Image Stacking | Price Model | Cross-Platform |
|---|---|---|---|---|---|
| Pixinsight | See site | Yes | Yes | Commercial | Yes |
| Photoshop | See site | No | No | Subscription | Yes |
| Affinity Photo | See site | No | No | One-time purchase | Limited |
| GIMP | See site | No | No | Free | Yes |
| Capture One | See site | No | No | Subscription | Limited |
| StarStax | See site | Limited | Yes | Free | Yes |
| Starry Night | See site | Limited | No | Commercial | Yes |
| Stellarium | See site | Limited | No | Free | Yes |
| Siril | See site | Yes | Yes | Free | Yes |
| Autostakkert | See site | Limited | Yes | Free | Limited |
Highlighted rows are featured placements. Competitor details are set by each platform, so confirm on their site before buying.
The 10 best best software for astrophotography processing tools
Pixinsight
See sitePixInsight is an advanced modular image processing platform purpose-built for astronomical work. It handles image stacking, calibration, alignment, and detailed processing in a single environment with industry-leading algorithms for astronomical data.
Pros
- Specialized for astronomical image processing with tools unavailable elsewhere
- Handles complex stacking, calibration, and registration workflows
- Portable across FreeBSD, Linux, Mac OS X, and Windows
- Modular architecture allows customization for specific needs
Cons
- Steep learning curve and complex interface
- No free tier; commercial license required
- Expensive compared to general-purpose alternatives
Best for: Professional astrophotographers and serious hobbyists processing deep-sky images
Photoshop
See sitePhotoshop is a professional image editor widely used in astrophotography for post-processing and detailed retouching. While not specialized for astronomy, its advanced selection, color, and detail tools make it valuable for the final polish after stacking.
Pros
- Powerful selection and masking tools for isolating celestial objects
- Extensive color grading and tone mapping capabilities
- Industry-standard software with abundant tutorials for astrophotography workflows
- Widely adopted, ensuring compatibility and community support
Cons
- Requires subscription; expensive for occasional users
- Not designed for image stacking or calibration
- Steep learning curve for astronomical-specific techniques
Best for: Post-processing and detailed retouching after stacking is complete
Affinity Photo
See siteAffinity Photo is a professional image editor offering comprehensive tools for astronomical image processing. It provides powerful selection, adjustment, and detail enhancement capabilities as an alternative to Photoshop with a one-time purchase model.
Pros
- One-time purchase pricing model, no subscription required
- Professional-grade tools for color grading and detail enhancement
- Comprehensive selection and masking tools for astronomical subjects
- Cross-platform support for Mac and Windows
Cons
- Not specialized for astronomical stacking or calibration
- Requires purchasing separate versions for different platforms
- Learning curve similar to other professional editors
Best for: Post-processing celestial images with professional editing tools
GIMP
See siteGIMP is a free, open-source image editor used by astrophotographers for post-processing tasks. While lacking specialized astronomical features, its powerful tools and zero cost make it accessible for budget-conscious imagers needing final image adjustments.
Pros
- Completely free and open-source
- Extensive selection, color adjustment, and layer tools
- Available on all major operating systems
- Large community with astrophotography-focused tutorials and plugins
Cons
- Not designed for astronomical stacking or calibration
- Interface less intuitive than commercial alternatives
- Limited support for some advanced editing workflows
Best for: Budget-conscious astrophotographers performing post-processing adjustments
Capture One
See siteCapture One is professional photo editing software with advanced raw processing and handling capabilities. While designed primarily for traditional photography, its precision controls and raw workflow tools are useful for astrophotographers needing detailed raw file processing before stacking.
Pros
- Excellent raw file handling and processing engine
- Powerful color correction and grading tools
- Advanced tethering capabilities for telescope-connected workflows
- Professional-grade output quality
Cons
- Not specialized for astronomical stacking or image combination
- Primary focus on traditional photography workflows
- Subscription-based pricing model
Best for: Raw processing and color management in astrophotography workflows
StarStax
See siteStarStax is free software specifically designed for creating star trail images through automatic stacking of multiple exposures. It automates the alignment and combination process for star trail photography, simplifying what would otherwise be a complex manual task.
Pros
- Completely free software
- Purpose-built for star trail image creation
- Automatic alignment and stacking of exposures
- Simple interface focused on specific task
Cons
- Limited to star trail workflows; not suitable for other astrophotography types
- No raw image support
- Minimal post-processing capabilities beyond stacking
Best for: Creating star trail images from multiple exposures
Starry Night
See siteStarry Night is planetarium software that simulates the night sky and supports telescope control. It helps astrophotographers plan observations and identify celestial targets before imaging sessions, complementing image processing tools in the overall workflow.
Pros
- Accurate night sky simulation for mission planning
- Telescope control capabilities for automated targeting
- Detailed celestial object database for target identification
- User-friendly interface for astronomy planning
Cons
- Not an image processing tool; cannot process or stack images
- Focused on planning rather than post-processing workflows
- Does not handle raw astronomical data
Best for: Planning astrophotography sessions and identifying celestial targets
Stellarium
See siteStellarium is free planetarium software showing real-time night sky positions and celestial object locations. Like Starry Night, it serves as a planning and identification tool rather than image processing software, helping astrophotographers prepare for observing sessions.
Pros
- Completely free open-source software
- Accurate planetarium display for any time and location
- Large database of stars, nebulae, and galaxies
- Available on all major operating systems
Cons
- No image processing or stacking capabilities
- Limited to planning and identification tasks
- Not integrated with telescope or camera control
Best for: Planning astrophotography sessions and learning the night sky
Siril
See siteSiril is free image processing software specifically designed for astronomical image stacking and calibration. It handles the critical first stages of astrophotography workflows, combining raw frames with proper dark and flat calibration before detailed post-processing.
Pros
- Completely free and open-source software
- Purpose-built for astronomical stacking and calibration
- Handles dark frames, flat fields, and image registration
- Available on Windows, macOS, and Linux
Cons
- Specialized for stacking only; not suitable for detailed post-processing
- Learning curve for astronomical-specific calibration concepts
- Smaller community compared to general-purpose editors
Best for: Free astronomical image stacking and calibration workflows
Autostakkert
See siteAutoStakkert is free lucky imaging software designed for planetary imaging workflows. It automatically analyzes, aligns, and stacks video frames from high-speed planetary cameras, producing high-quality combined images from otherwise noisy individual frames.
Pros
- Completely free software
- Specialized for planetary imaging workflows
- Automatic frame analysis and alignment for video stacking
- Produces high-quality results from fast video captures
Cons
- Limited to planetary imaging; not suitable for deep-sky work
- Requires fast video camera input; not designed for traditional long exposures
- Minimal post-processing tools beyond stacking
Best for: Planetary imaging workflows using high-speed video cameras
How we chose
We verified information directly from official websites of each tool, focusing on their stated capabilities and category classification for astronomical image processing.
Our selection includes dedicated astrophotography software, general-purpose editors, specialized stacking tools, and planning aids that astrophotographers actually use in their workflows.
Frequently asked questions
What is the difference between image stacking software and post-processing editors?
Image stacking software aligns and combines multiple exposures into a single high-quality image, removing noise and increasing detail. Post-processing editors then refine colors, contrast, and details in the final stacked image. Most astrophotographers use both in sequence.
Can I use general-purpose editors like Photoshop for astrophotography?
Yes, but only for post-processing after stacking. Photoshop and Affinity Photo lack the specialized algorithms needed for astronomical calibration and alignment, so they work best as final polish tools after dedicated stacking software has done the heavy lifting.
Is PixInsight worth the cost if free alternatives exist?
For professional deep-sky astrophotography, PixInsight's specialized tools and superior algorithms justify the investment. For planetary imaging or casual processing, free tools like Siril or AutoStakkert may suffice. Consider your specific needs and budget before committing.
Do I need planetarium software like Stellarium or Starry Night?
Planetarium software helps you plan where to point your telescope and what objects are visible at specific times. While not required for image processing, most serious astrophotographers use them as the first step before a session begins.
What workflow should I follow when processing astrophotography images?
Typical workflow: use planetarium software for planning, capture raw frames with your camera, use stacking software like Siril or PixInsight for calibration and combination, then use post-processing editors like Photoshop or GIMP for final color and contrast adjustments.
Can I process images with just free software?
Yes. Siril for deep-sky stacking, AutoStakkert for planetary work, and GIMP for post-processing create a capable free astrophotography processing chain. You sacrifice some specialized tools available in PixInsight but maintain full functionality.
The bottom line
Most astrophotographers use multiple tools in sequence: dedicated stacking software first, then general editors for final polish.