The Grader UI

A fast, keyboard-driven UI for reviewing and grading subs. It's the same UI everywhere: the desktop app ships it built in (no server or browser needed), and psf-guard server serves the identical interface to any browser for NAS and remote setups. Grades stay in the active catalog. When the active catalog is an existing Target Scheduler database, the scheduler can use the grades to replace rejected frames.

Simple

Build or open a catalog

Start from FITS folders or an existing Target Scheduler database.

Getting started →

Overview dashboard

Overview showing recent projects and real narrowband frames — Recent projects and frames, targets, image counts, and grading progress across every configured database.

The overview aggregates all your configured catalogs: project and target statistics, completion percentages, real-time file discovery status, and filter usage. Click through any project or target to land in its grid. After grading, use ⬇ Export on a project or target to build clean stacking input; see Export for Stacking.

Compact project card with a newest-frame marker and relative capture time — Recent projects group by capture date and mark the newest frame, with a relative capture time on every thumbnail.

Unified project and target picker with type-ahead search — The header picker searches projects and targets, groups recent work first, and expands each project into its targets.

Image grid

Wide desktop grid showing real Flaming Star H-alpha frames and the compact controls — Real Flaming Star H-alpha frames in the cleaned desktop grid. The compact toolbar keeps every review control in stable rows.

Smart filtering — project, target, grading status, filter, date range, search, image size, and filter/date/session grouping.
Batch operations — multi-select with Shift+Click / Ctrl+Click, or move the cursor with arrows and press Space. Accept, reject, or unmark the whole selection.
Stable review position — preview generation, stack status, and database refreshes preserve the first visible image instead of moving the page.
Metadata on every card — HFR, star counts, acquisition details.
Smart loading — fast previews first, full resolution on zoom. Previews generate on demand in the background, so a fresh install is browsable immediately; a "Generating…" badge shows while the queue works.

Responsive narrow-window layout

Flaming Star H-alpha grid with the controls wrapped for a narrow window — The same controls wrap into short rows without hiding the image cursor or grading state.

Comparison mode

Side-by-side comparison with synchronized zoom — Synchronized zoom and pan; grade either or both frames without leaving the view.

Put two frames side by side with synchronized (or independent) zoom and pan — ideal for judging a borderline frame against a known-good neighbor. Accept, reject, or unmark both images at once.

Sky context and plate solving

Open a frame to see catalog objects expected near its FITS or catalog target coordinates. If it has no embedded WCS, choose Solve field or press O to run Seiza against the pixels. A successful solution enables the sky overlay with catalog labels, outlines, an RA/Dec grid, solved scale, and target offset. See Sky Context & Plate Solving for catalog setup, Docker configuration, validation, and the API.

Settings showing installed Seiza catalogs and available sky features — Settings shows which catalog features work and installs or validates the Seiza sky data when database management is enabled.

Sequence view

Sequence analysis with two poor frames, nine good frames, and solved-center scatter — One quality view combines image conditions, PSF/guiding metrics, solved-center scatter, and field-relative pointing evidence.

The Sequence view plots per-frame quality over a night: HFR, star counts, and — once you press Scan Quality — spatial, photometric, and pixel-derived astrometry signals. Flagged runs are classified (occlusion, clouds, sky brightening, off target, pointing jump/drift, or unsolved). The analyzer keeps stable deliberate framing segments advisory, while returned excursions and within-segment drift remain rejectable. The selectors focus the evidence, and a per-image review appears before a recommended rejection is written. See Quality Screening and Astrometry Quality.

Keyboard shortcuts

Key	Action	Key	Action
K / →	Next image	A	Accept
J / ←	Previous image	X	Reject
↑ / ↓	Nearest grid row	Space	Toggle selection
Enter	Open image	C	Compare
Esc	Clear / close	U	Unmark
S	Stars overlay	+ / −	Zoom
O	Solve / sky overlay
Ctrl+Z	Undo	Ctrl+Y	Redo

Where grades go

Every action updates gradingStatus in the active catalog, with undo and redo tracked in the UI. PSF Guard uses the Target Scheduler database mapping for catalogs it creates. If you open or sync a live Target Scheduler database, the scheduler can count accepted images against each exposure plan and queue replacements for rejected frames.