An astrophotography image catalog manager, with optional N.I.N.A. and Target Scheduler integration. Catalog your FITS files in place, browse and grade frames by target, session, and filter, and let it flag clouds, obstructions, tracking loss, and bad pointing — then preview stacks and export the keepers.
More from us: seiza.fyi — live plate solving in your browser, plus desktop apps for FITS browsing.
Star count and HFR miss ruined frames. Measured on a real session: a tree line occluding the field left star counts within normal variation, and HFR stayed flat until the frame was more than 60% blocked. A thin cloud veil dimmed every star by 37% — and the frame was still Accepted by conventional grading. PSF Guard screens with signals that are local, photometric, and temporal — classical statistics calibrated on real sessions.
Build a catalog from FITS folders or open an existing Target Scheduler database. Browse by target, session, filter, date, and grade while the source files stay in place.
One grader UI, in the desktop app or any browser: auto-stretched previews, zoom and pan, side-by-side comparison with synchronized zoom, batch operations, keyboard-driven workflow, and full undo/redo.
Spatial metrics, cross-frame photometry, and fresh plate solutions catch occlusion, clouds, thin veils, errant light, off-target frames, and tracking loss — with evidence explaining every verdict.
See expected catalog objects from known coordinates, solve image pixels on demand with Seiza, and overlay labels, object outlines, an RA/Dec grid, and the measured target offset.
Integrate a target's graded frames per channel with Seiza registration, combine them into LRGB or SHO/HOO/Foraxx color previews with background extraction and opt-in deconvolution, and download the linear FITS — before committing hours to a full run.
Open a Target Scheduler database or sync a separate telescope copy. Reviewed grades keep its acquired-image counts accurate, so it can replace rejected frames.
Build a catalog from plain FITS folders, derive projects, coordinates, shared exposure templates, and plans from headers, then add quality data in the background.
Move rejected frames and their sidecars out of the directory tree your stacking software scans. Idempotent, recorded, and fully reversible — restore never overwrites.
Sync projects, captured images, and grades between the telescope's database and your grading machine — pull to refresh, grade locally, push grades back.
A port of N.I.N.A.'s detector plus a HocusFocus-inspired detector, with Gaussian/Moffat PSF fitting, annotated star maps, and residual visualizations.
Header coordinates provide immediate catalog context. When the frame has no
embedded WCS, choose Solve field or press O:
PSF Guard tries a fast hinted solve, falls back to the blind index when
installed, caches the result, and turns on the shared Seiza overlay.
Every flagged frame can be rendered as an annotated diagnostic: the analysis grid is overlaid on the image, colored by the signal that fired, with the verdict and metrics in the caption. The diagnostic shows which rule fired and why.
Live-stack the accepted frames of a target right inside the grader — your current grades and sequence checks select the inputs. Combine cached channel stacks into LRGB or narrowband color with Seiza background extraction, editable processing, and opt-in deconvolution; then export the non-rejected lights into a WBPP-ready folder, zip download, or instant local hardlinks.
Desktop app, Docker container, standalone binary, or Fedora RPM — one tool, wherever your images live.
Native installers for Windows (.msi / NSIS setup with CLI on
PATH), macOS (.dmg, Apple Silicon), and Linux
(.deb / AppImage).
For NAS boxes and home servers. The catalog mount must be writable so grades and plans can be saved.
docker run -d -p 3000:3000 \
-v /path/to/catalog.sqlite:/data/database.sqlite \
-v /path/to/images:/images:ro \
ghcr.io/theatrus/psf-guard:latestSingle binary for scripting and servers. Screen a night in one command:
psf-guard screen-fits ./LIGHT --annotate ./diag
psf-guard server catalog.sqlite ./imagesPrebuilt packages for Fedora 43/44 with a psf-guard.service
systemd unit for running the grader as a daemon.
sudo dnf install ./psf-guard-*.x86_64.rpmMore projects from theatr.us