Post-processing software
Astro images rarely show their true potential straight out of the camera. Post-processing is where the magic happens — stacking frames, reducing noise and revealing detail invisible to the naked eye. Here are some of the tools our members use and recommend.
| Description | Cost | |
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Autostakkert 4 is the go-to free stacking tool for planetary, lunar and solar imaging. It analyses video frames or image sequences, ranks them by quality, aligns and stacks the sharpest frames to produce a cleaner, more detailed result. Fast, reliable and regularly updated — an essential tool for any planetary imager. | Free or make a donation |
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Registax has been a staple of planetary imaging for over 20 years. While AutoStakkert has taken over much of the stacking work, RegiStax remains unrivalled for its Wavelet sharpening tools, which bring out extraordinary surface detail in planets and the Moon. Many imagers use both together for best results. | Free |
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AstroSurface is a free Windows-based processing tool covering both planetary and deep-sky imaging. Developed and regularly updated by Lucien Pesquer, it combines stacking, wavelet sharpening and deconvolution in a single package. An excellent free alternative to RegiStax for planetary work, with version W1 introducing local processing capabilities. Windows only. |
Free |
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Gimp (GNU Image Manipulation Program) is a powerful, free alternative to Photoshop, available for Windows, Mac and Linux. For astrophotography it handles levels, curves, colour balance and noise reduction effectively. It has a steeper learning curve than some tools, but the wealth of online tutorials makes it very accessible. | Free |
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Affinity Photo- Affinity Photo is a professional-grade image editor at a fraction of the cost of Adobe Photoshop, with no subscription required. It handles RAW files, offers advanced layer-based editing, and has become increasingly popular in the astrophotography community. An excellent mid-point between free tools and the cost of PixInsight. | Free Tier or Paid |
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Graxpert GraXpert is a dedicated gradient and background extraction tool — tackling one of the most common problems in astrophotography: uneven sky backgrounds caused by light pollution or vignetting. It uses AI-driven algorithms to intelligently remove gradients while preserving nebula and galaxy detail. Free to use and works as a standalone or plugin. | Free |
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Seti Astro Suit Pro Created by Frank Biggs, Seti Astro Suite Pro is a collection of free processing scripts and tools, primarily designed for use within PixInsight but also usable standalone. It covers everything from gradient removal to star reduction and noise processing. Frank accepts donations to support continued development — well worth contributing if you find it useful. | Free or make a donation |
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Siril is a powerful, free and open-source astrophotography processing application for Windows, Mac and Linux. It handles the full deep-sky workflow — calibration frames, stacking, background extraction, colour calibration and stretching — in a single package. Widely regarded as the best free alternative to PixInsight for deep-sky imaging. |
Free |
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Pixinsight is widely considered the industry standard for serious astrophotography post-processing. Built specifically for astronomical imaging, it offers unmatched tools for calibration, stacking, noise reduction, deconvolution and colour processing. The learning curve is steep and the cost reflects its professional status, but the results speak for themselves. A one-time licence fee applies. | Paid |