Solar / Lunar / Planetary Stacking

The "thousands of frames in a SER, keep the sharpest 5%" pipeline. Different from deep-sky stacking in every way: short focal length doesn't matter, sub-arcsecond seeing limits do, you shoot at 100+ FPS at high gain, then run lucky imaging (rank by sharpness, stack only the best frames). Software stack is small, free, and largely Win-only — but it works on Wine / VM on Mac/Linux.

For the capture half see Image Acquisition (FireCapture); for solar-specific gear see Astro Cameras & Sensors; for outputs that go on into general post see Image Editing and Photo RAW Editors.

The classic free Windows pipeline

• ★ ★ AutoStakkert! 4 (AS!4) — freeware, Win (Wine on Linux/Mac fine). The lucky-imaging stacker — analyzes each frame in a SER, ranks by quality, aligns by hundreds of alignment points (AP grid), stacks the top N% per AP for atmospheric-cell-aware sharpness. The unambiguous workhorse of planetary imaging since 2015. Free.
  • https://www.autostakkert.com
• ★ RegiStax 6 — freeware, Win. The legacy stacker; mostly used in 2026 for its wavelet sharpening rather than its stacker (AutoStakkert! is better). Open RegiStax 6 → Wavelets → load AutoStakkert!'s output → tweak six wavelet sliders → save. Free.
  • https://www.astronomie.be/registax
• ★ PIPP (Planetary Imaging PreProcessor) — freeware, Win. SER/AVI pre-processor: cropping, centering, debayering, format conversion. Run before AutoStakkert! to keep file sizes manageable. Free.
• ★ WinJUPOS — freeware, Win. Specialty tool for derotation: Jupiter rotates so fast (~9.9-h day) that a ten-minute capture smears its features; WinJUPOS measures rotation and de-rotates, allowing you to combine multiple AS!4 outputs into a single sharper image. Also handles ephemeris for moons / Great Red Spot longitude / shadow transits. Free; the planetary equivalent of darks-and-flats. Saturn, Mars also benefit.
  • http://jupos.org
• AstroSurface — free Win/Wine. Newer all-in-one (capture analysis + stack + wavelets); growing share; might overtake AS!4 in coming years.

Solar-specific

• ★ ImPPG (Image Post-Processor) — GPL, Win/Linux/Mac. Solar-grade unsharp masking and Lucy-Richardson deconvolution; the OSS sharpening tool of choice for white-light and Hα solar stacks. Cross-platform.
  • https://greatattractor.github.io/imppg/
• Solar System Aligner (free) — niche aligner for full-disk Hα mosaics.
• Sharpcap LiveStack solar mode (paid SharpCap Pro) — for live H-alpha viewing.
• Specialised solar tools: GoSky stitching (free), Adobe Photoshop "False Color from H-α" workflows.

Lunar-specific

• AS!4 + RegiStax 6 wavelets handles lunar fine.
• LRGB-mosaic stitching: Microsoft ICE (free, sunset but mirrored), Hugin (FOSS), AutoPano Giga (sunset paid). See Photo Panorama / HDR.

Atmospheric Dispersion Corrector (ADC) helpers

When the planet is at low altitude, atmospheric refraction smears it into a rainbow. Hardware ADCs (ZWO, Pierro Astro) fix it physically. FireCapture's ADC tuning aid (free) shows R/G/B channel offsets live to dial in the ADC. SharpCap Pro has equivalent.

A typical planetary pipeline

1. Capture in FireCapture: SER, ROI 800×600 around the planet, 100+ FPS, ~3-min runs.
2. PIPP: crop, center, convert to AVI/SER as needed.
3. AutoStakkert! 4: open SER, set 50 alignment points, stack top 25% → 16-bit TIFF.
4. WinJUPOS (Jupiter, Mars, Saturn): de-rotate multiple stacks into a single longer-effective-exposure result.
5. RegiStax 6 wavelets or AstroSurface: sharpen carefully, tweak six layers.
6. Photoshop / GIMP / Affinity Photo: final color saturation / minor curves.

A typical solar pipeline

1. Capture in FireCapture or SharpCap: SER, ROI ~1500×1500 for a full disk at 1500 mm.
2. PIPP: rotate, center the disk.
3. AutoStakkert! 4 with surface mode (not feature) for white-light; quad-AP grid.
4. ImPPG for unsharp + L-R deconvolution.
5. Photoshop or Affinity Photo for final tone / colorisation (orange tint, corona blending).

Mac / Linux notes

• AutoStakkert!, PIPP, RegiStax, WinJUPOS all run fine under Wine on Linux/Mac.
• AstroSurface has native Linux/Mac binaries.
• ImPPG is cross-platform native.
• lxnstack (free Linux) is a niche Linux-native stacker but feature-poor compared to AS!4-on-Wine.

License / pricing

• All headline tools above are free (freeware or GPL). Paid tools in this niche are uncommon — Stellar Imaging is one, MaxIm DL has planetary tools, but neither is the community standard.

Pick this if…

• Default planetary stacker: AutoStakkert! 4 (with PIPP upstream).
• Final sharpening: RegiStax 6 wavelets or ImPPG.
• Jupiter / Mars / Saturn long captures: add WinJUPOS for derotation.
• Solar processing: ImPPG (cross-platform) is the OSS pick.
• One-app cross-platform alternative to AS!4 + RegiStax: AstroSurface.
• Mac / Linux user: Wine the AS!4 chain or use AstroSurface natively.