Sky Intruders
Identify what crossed your subframes, and hunt the hidden treasures in your images: quasars, galaxies, asteroids.
Overview
Streaks across your subframes? Sky Intruders does more than detect them: it identifies them. The Night trails mode scans a night of light frames (never touching your files), detects trails on the registered difference, so nebulosity cannot fool it, then cross-matches every pass against CelesTrak's public orbital elements propagated with SGP4. The night log reads "02:13, STARLINK-4512", not "trail". Whatever matches no satellite is tested against the radiants of the active meteor showers; slow, coherent movers across frames become asteroid candidates, and parallel bundles are grouped into satellite trains or aircraft. You get an annotated composite, every streak labelled with the satellite's name, country flag, altitude and speed, and a bilingual night log with fun stats, persistent personal records and a ready-to-post report.
Treasure Hunt flips the logic. Point it at a plate-solved final image: it digs through the deep catalogues to reveal what you captured without knowing it, HyperLEDA galaxies, Milliquas quasars with their redshift, MASH planetary nebulae, asteroids that drifted through the field at the moment of capture. Every catalogue position is then measured on your image, so the report honestly separates what you truly captured from what sits in the field, below your noise floor. And the story writes itself: "this four-pixel smudge is a quasar at z = 2.2, its light left 10.7 billion years ago, before the Sun existed." The result renders as an annotated star chart, with leader lines, corner cards, Hipparcos stars and NGC/IC neighbours for context, and exports as a standalone illustrated HTML post, ready for a forum.
Everything runs inside PixInsight, in pure PJSR: no native helper to install or trust. Online catalogues are cached on disk, and a network outage is reported as such, never read as "zero finds".
Features
Trail detection
Your subframes are registered internally and trails are searched on the difference: nebulosity does not fool the detection. Read-only, your files are never modified.
Named satellites
Cross-matched against CelesTrak TLEs (active satellites and recent launches, merged and cached), propagated with SGP4. Every identification carries a confidence grade, and survives a missing plate solve thanks to a field-orientation fit.
Meteors, trains and asteroids
Unmatched trails are tested against the radiants of the active IAU meteor showers. A slow, coherent drift across frames becomes an asteroid candidate; parallel bundles are grouped into satellite trains or aircraft.
Annotated composite
The night's best frame, picked on a quality score, with every streak highlighted and labelled: name, country flag, altitude, angular speed, launch year, status. Labels avoid collisions, and an optional ghost layer shows the predicted crossers.
Shareable night log
A bilingual logbook of your visitors, with the night's statistics, your personal records kept from session to session, and a report ready to post on a forum.
Honest treasure hunt
On your plate-solved final image: galaxies, quasars with their redshift, planetary nebulae, passing asteroids. Every catalogue position is measured on your pixels, with decoy apertures and a magnitude consistency check: a magnitude-20 asteroid will never be sold to you as "captured".
Star chart and story
Redshifts become light-travel times, sizes become smudges a few pixels across. The render is a sober star chart, accent colour of your choosing, elbowed leader lines and corner cards, exportable as a standalone illustrated HTML post.
Online catalogues, cached
CelesTrak, VizieR (HyperLEDA, Milliquas, MASH, Hipparcos) and SkyBoT, queried through PixInsight's own networking, with no native helper. Responses are cached on disk, and an outage is reported as such, never read as "zero finds".
Screenshots
Install
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01
Add the CaeloWorks repository
In PixInsight, open Resources → Updates → Manage Repositories and add the CaeloWorks repository URL:
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02
Check for updates
Run Resources → Updates → Check for Updates and accept: PixInsight downloads and installs the script.
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03
Restart PixInsight
Relaunch the application: the script shows up in the Script menu. Future updates then arrive automatically.
Each script can also be installed manually: download the .js file and add its folder through Script → Feature Scripts. See the script page.
Changelog
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0.2.1 2026-08-17
Bug fixes. The slow-mover (asteroid-candidate) detector no longer floods plate-solved nights with false tracks from sensor artifacts: a candidate now needs 4 points, a constant-velocity fit within 2.5″ rms, strictly monotonic motion of at least 10″, and families of tracks sharing one velocity vector (sensor-fixed points carried by a registration drift) are dropped as a whole. On the reference set, a storm of 126 candidates falls to zero while real movers are kept. Treasure Hunt now tells a catalogue outage from an empty field: a query that fails, times out or answers with something other than data (a maintenance or captive-portal page) is reported as such, the report names the silent catalogues, and a failed query is no longer cached as an empty field for 30 days.
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0.2.0 2026-07-16
Identified satellites now say what they are: in service, out of service, rocket body or debris, from the catalogue. Bright late-night trails no longer come out "uncatalogued": the orbital element list grows from 19,000 to 31,000 objects and finally covers rocket bodies, defunct payloads and debris, exactly the population still sunlit deep in the night. Fixes: on a plate-solved image, strict identification simply never worked and silently fell back to the field orientation; both the frame of comparison and the observer position were off (up to 24 km of site error). On the reference night, a QIANFAN-2 trail's residual drops from 0.35° to 0.009°, that is 32 arcseconds, and two more satellites are named. Finally, a fast satellite crossing the field early in a long exposure is no longer culled before being examined, and a storm of false "asteroid candidates" caused by sensor artifacts is now detected and reported as such rather than listed.
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0.1.1 2026-07-11
The script now has its icon in PixInsight (Script menu, Feature Scripts and the dialog emblem) and joins the CaeloWorks menu category. Revalidated on the thirteen-frame reference night: same result as the previous version, twelve trails, eight named satellites, four honestly uncatalogued.
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0.1.0 2026-07-09
First public release (beta, GPL-3.0), distributed through the CaeloWorks update repository: Night trails mode (satellites named from TLE and SGP4, meteors, asteroid candidates, annotated composite and night log) and Treasure Hunt mode (galaxies, quasars, planetary nebulae and asteroids, star chart and HTML report).