Astro Catalogues & Data

The "where does the planetarium / solver / pass predictor get its data?" reference. Everything astronomical sits on a small set of public catalogues — most freely downloadable, several updated daily. Knowing which catalogue, which version, and where to fetch it is useful when configuring plate solvers, planetariums, satellite trackers, or your own scripted analyses.

For the software that consumes these see Planetariums, Plate Solving, Satellite Tracking, Spectroscopy, Citizen Science; for self-hosting these large catalogue files see Self-Hosted Photos & Media for the hardware patterns.

Stellar catalogues

• ★ ★ Gaia DR3 / DR4 — ESA mission; astrometry + photometry for ~1.8 billion stars, parallax / proper motion for the brighter ones. The 2026 reference for everything stellar. Free; bundled into Stellarium / KStars / ASTAP / astrometry.net. DR4 expected late 2026 with extended-mission data.
  • https://www.cosmos.esa.int/web/gaia/data-release-3
• Hipparcos / Tycho-2 — pre-Gaia astrometry; ~2.5 million stars; older but still used as legacy reference in some plate solvers.
• 2MASS — IR all-sky; ~470 million sources; useful for star-confused-fields plate solving.
• UCAC4 / UCAC5 — astrometry catalogue, ~113 million stars; widely bundled.
• APASS DR9 — photometric standards; useful for variable-star photometry zeros.

Deep-sky catalogues

• ★ Messier (M1-110) — Charles Messier 1781; the classic 110 brightest non-stellar objects. Bundled everywhere.
• ★ NGC / IC (New General Catalogue / Index Catalogue) — ~13,000 deep-sky objects; J. L. E. Dreyer late-1800s; modernised by Wolfgang Steinicke. Bundled.
• Caldwell — Sir Patrick Moore's "best Messier-overlooked" 109 objects; bundled.
• Sharpless — emission nebulae catalogue (Sh2-1 to Sh2-313).
• Abell — galaxy clusters.
• Hickson — compact galaxy groups.
• PGC / LEDA — Principal Galaxies Catalogue, ~1.5 million galaxies.
• SDSS DR17 — 5-band photometric survey; spectra of ~5 million objects; free.

Cometary / asteroidal

• ★ Minor Planet Center (MPC) elements — Cambridge MA; the asteroid / comet orbital element source. Updated nightly. Bundled into Stellarium / KStars / Cartes du Ciel.
  • https://www.minorplanetcenter.net
• JPL Horizons — NASA JPL ephemeris service; arbitrary-precision; web + telnet + API.
• TheSkyLive.com — friendly web view of MPC + Horizons data.

Satellite / orbital element data

• ★ NORAD Two-Line Elements (TLEs) — see Satellite Tracking. Celestrak (free, public) and Space-Track.org (free with US-government registration) are the canonical sources. Refreshed daily / weekly.
• Vallado SGP4 — the propagator that turns TLEs into positions; free reference implementations in Python, C, Rust, JS.

Survey imagery

• HiPS (Hierarchical Progressive Surveys) — pyramidal tiled all-sky imagery; DSS2 / SDSS / PanSTARRS / 2MASS / Gaia / WISE / NVSS all available.
  • Aladin Lite — free web viewer.
  • Aladin Desktop — free Java app.
  • Stellarium / KStars consume HiPS as overlay tiles.
• JWST archive (MAST) — public after proprietary period; free; high-quality pre-processed data.
• Hubble Legacy Archive — same.
• ESO archive — VLT, ALMA, etc., free.

Time / earth-orientation

• IERS bulletins — leap seconds, UT1-UTC; free.
• JPL DE441 / DE440 ephemeris — solar-system body positions; free; used by all serious tools.

Satellite imagery

• NASA Worldview — daily satellite views; free.
• NOAA / GOES products — see Weather Satellites.

Spectral / line atlases

• NIST ASD (Atomic Spectra Database) — free; line lists for elements; used by ISIS / VSpec.
• HITRAN — molecular line database; free with registration.
• VSX (AAVSO Variable Star Index) — free.

Astrobiology / exoplanet

• NASA Exoplanet Archive — confirmed planets + candidates; free.
• TESS Input Catalog (TIC) — free.
• Kepler / K2 / Cheops archives — free.

Where the bundles live

• Stellarium DSO ships ~1.5 GB of star + DSO catalogues by default.
• KStars bundles ~150 MB; pulls more on demand.
• astrometry.net index files — by FoV; ~50 GB if you want every band; ~1 GB for one focal length.
• ASTAP databases — G05 (~120 MB), V17 (~1 GB), H18 (Gaia-based, ~3-5 GB).
• Skyfield ephemerides — DE421 ~17 MB, DE441 ~3 GB.

Self-hosting / mirroring

• MAST / ESO / SDSS bulk download — measured in TB; consider only if you're processing systematically.
• Aladin Lite tiles — small (~MB) per region; web-bundleable.
• Off-grid stations: SatNOGS / observatories may want local mirrors of Celestrak TLEs / MPC; cron + curl handles it.

What's changing in 2024–2026

• Gaia DR4 late-2026 release; deeper astrometry; better proper motions; will refresh every plate solver's database.
• JWST archive opened up; ~500 hours of pretty pictures and instrument data freely downloadable.
• Vera Rubin LSST first light 2025; full survey data 2026+; will produce ~20 TB / night; pro/am access via DR.
• Chinese / Indian / EU mission data — increasingly open.
• AI-tagged catalogue services (Aladin chat-with-the-sky tools; alpha as of 2026).

License / pricing

• All catalogues listed are FREE for personal / hobby / academic use.
• Bulk-download infrastructure sometimes requires registration but no payment.
• Commercial re-distribution of Gaia / SDSS / etc. has license-of-source requirements; check each.

Pick this if…

• Stars: Gaia DR3 (DR4 when released).
• Deep-sky names: Messier / NGC / IC.
• Asteroids / comets: MPC + JPL Horizons.
• Satellites: Celestrak TLEs.
• Survey imagery: HiPS via Aladin / Stellarium.
• Pro archives for re-processing: MAST (HST/JWST), ESO archive.
• Variable star reference: AAVSO VSX.
• Exoplanets: NASA Exoplanet Archive.
• Just keep an offline mirror for a Pi station: TLE cron + KStars defaults + astrometry.net index for your FoV.