Stack Previews

Check an integration before committing hours to calibration: PSF Guard live-stacks the graded frames of a target right inside the grader — per channel, in color, and with your current grades and sequence checks.

Per-channel previews from graded frames

From a project's stack panel, PSF Guard integrates the selected or visible frames per exact target and filter with Seiza registration. The selection selection policy runs before registration: catalog rejects and current sequence-analysis regrade recommendations are excluded before registration, so the preview shows what your accepted data actually stacks into. The latest successful result for each channel is kept durably in the cache; rebuilding one channel never discards its siblings.

A three-frame B-channel project stack preview card — On-demand, uncalibrated integration grouped by exact target and channel, with live phase progress.

Per-frame Seiza registration and admission details — Every input's quality exclusion, reference choice, match count, registration RMS, and admission decision is retained with the result.

Inspect at full resolution, stretch, download

The preview opens in the same inspector the grader uses — zoom, pan, fit, and one-pixel-per-pixel — and the display stretch is a parameterized Seiza stretch you can adjust or revert without recomputing the integration. The cached result stays linear: download it as FITS and drop it straight into your processing workflow.

Native-resolution stack inspection with zoom and pan — Familiar zoom, pan, fit, and 1:1 controls on the full-resolution result.

Parameterized Seiza display stretch controls on a stack preview — Apply or revert display stretches; the cached integration underneath remains linear.

Color composition: LRGB and narrowband palettes

When the required channel stacks exist, combine them without rebuilding the integrations. PSF Guard discovers unambiguous L/R/G/B and Ha/OIII/SII roles from the durable mono stacks, registers filters onto the luminance or H-alpha reference, and calls Seiza's color combiners. Available palettes are SHO, SOH, HSO, HOS, OSH, OHS, and HOO plus Foraxx-SHO and Foraxx-HOO; targets without SII automatically expose only the HOO variants.

Real Gulf of Mexico Foraxx SHO preview built from PSF Guard channel stacks — A real Gulf of Mexico (NGC 7000) Foraxx SHO preview from six accepted acquisitions — two each in H-alpha, OIII, and SII.

The same channel stacks combined as standard SHO — The same three linear channel stacks recombined as standard SHO — switching palettes never re-integrates.

Rebuilt source channels mark remembered color results stale without hiding them, so you always know when a combination no longer reflects the freshest channel data. Color outputs are cached with full provenance (source jobs, palette, policy, Seiza revision) as screen and native PNG plus an RGB 32-bit-float FITS whose header records the palette and linear-versus-display transfer semantics.

Background extraction and processing controls

Color previews fit and subtract each input channel's background before cross-filter registration, using Seiza background extraction with per-channel fit diagnostics. The editable processing stack exposes additive or multiplicative correction controls and ordered per-input and output stretch stacks — with complete phase progress while a job runs.

Background extraction controls and per-channel fit diagnostics from a real narrowband preview — Resolved fit evidence and the editable background model: this real run accepted 73/96 H-alpha, 78/96 OIII, and 95/96 SII sample locations while rejecting noisy or source-contaminated fits.

Opt-in deconvolution

Stack previews can apply Seiza deconvolution as an opt-in processing step, sharpening the preview without touching the cached linear integration. Like the display stretch, it is a reversible view decision — toggle it, compare, and download either representation.

Take the data out for real stacking

When the preview convinces you the data is worth a full run, export the non-rejected lights straight into your stacking pipeline. Rejects are never exported; ungraded frames are opt-in. Desktop, browser, CLI, and API modes all produce the same WBPP-style layout — <target>/LIGHT/<filter>/ — that PixInsight WBPP and Siril group automatically.

Open the Export for Stacking guide → for desktop and browser steps, CLI filters, repeat-export behavior, API examples, and troubleshooting.