Live Stacking PRO
Real-time deep-sky stacking with calibration, alignment, true drizzle (1.0/1.5/2.0, pixfrac 0.5-1.0), quality gate by alignment error, sigma-clipping, weighted stacking, diagnostics (FWHM/coverage/variance), and on-the-fly stretch. Designed to help you decide when to stop and export a top-quality result.
Quick Start (5 min)
- Prepare folders: Lights, Darks, Flats (+ Bias if used).
- Select Lights, optional fast Temp SSD and Output folder.
- Enable Calibration (masters) -> Start Live Stacking.
- Watch Preview, Histogram, FWHM, and Coverage.
- Save the stack and optional Drizzle Maps (coverage/variance).
All Controls
| Control | Default / Range | What it does | When to use |
|---|---|---|---|
| Image/Temp/Output | - | Source, workspace and export locations | Temp on NVMe for speed |
| Watch folder | Off | Auto-ingest new frames | Live capture/EAA |
| Calibration | Load masters | Dark->Flat->Bias before alignment | Always for flats; darks as needed |
| Method | mean | median | sigma_clip | Combine frames | sigma_clip for trails/hot pixels |
| Weighted stacking | On | Weights sharp/high-SNR frames | Variable seeing |
| Drizzle | Off | True drizzle with coverage/variance maps | Under-sampled + dither |
| Scale | 1.0 / 1.5 / 2.0 | Drizzle up-sampling | 2x only with strong SNR |
| pixfrac | 0.5-1.0 | Drop size (crisp vs smooth) | 0.8-1.0 typical |
| Align error reject > | 0.1-2.0 | Reject mis-registered frames | Tighten with wind/poor seeing |
| Sigma (clip) | ~1.5-3.0 | Reject pixel outliers | Trails/satellites/cosmic hits |
| Stretch | stf | arcsinh | hdr_local | masked | linear | Preview/Export tone map | arcsinh for faint nebulae |
| Post (optional) | wavelet, gradient, star-reduction, PSF decon | Gentle cleanup | High ISO/short stacks |
Recipes
- M42: Drizzle 1.5x, pixfrac 0.9-1.0, sigma=2.0-2.5, arcsinh; star reduction mild.
- Faint widefield: Drizzle 2x, pixfrac 0.8-0.9 (dither!), align err <= 0.5-0.7, arcsinh.
- Small galaxy: Drizzle 2x, pixfrac 0.7-0.8, align err <= 0.4-0.6, hdr_local; optional light decon.
- Open cluster: Classic mean/median, no drizzle, conservative stretch.
Diagnostics
- FWHM uptrend -> focus drift/seeing worsened -> pause, refocus, resume.
- Coverage dark edges -> keep going or increase dither amplitude.
- Variance hot areas -> noisy regions; consider longer total time.
Troubleshooting
- Grayscale preview -> enable Debayer (OSC).
- Egg-shaped stars -> tighten align error reject and ensure good guiding.
- Patchy drizzle -> increase frames/dither or raise pixfrac to 0.9-1.0.
- Saved image != Preview -> enable Preview Post-Processing or export linear for later post.
Updated 2026-05-17