Astronomy generator data

astro-profile.json is the authoritative ground/all-sky configuration, and astro-hubble-profile.json is the independent Hubble observer configuration. Both store the calculation timestamp, stable observer and instrument IDs, visibility constraints, and catalog paths. timestamp accepts an ISO-8601 UTC instant or the literal now; now is sampled exactly once when generate-astro starts.

The checked-in ground profile uses the generation-session timestamp 2026-08-05T01:59:44Z and San Francisco, California, USA (37.7749, -122.4194, 16 m elevation). The orientation defaults to conventional celestial handedness with right ascension increasing leftward and RA 12h at the projection center. The transient window defaults to seven days. Its observer ID is ground-multiband and its instrument ID is generic-ground-multiband.

The Hubble profile uses the same instant but selects NORAD 20580 from the checked Orbital Technosphere CelesTrak science OMM catalog. Its observer ID is hubble; its hst-composite instrument enables infrared, optical, and ultraviolet sources subject to a 20° Earth-limb clearance and 60.3° Sun avoidance. It produces only astro-observer-hubble-*; the ground product is named astro-observer-ground-multiband-* so the platforms cannot be confused.

Run make fetch-astro-data to refresh the bounded catalog snapshots:

• 500 Gaia DR3 sources with phot_g_mean_mag < 5.5, ordered by magnitude;
• 250 nearby confirmed-planet rows from the NASA Exoplanet Archive;
• JPL Small-Body Database records for four representative asteroids and three representative comets.

The fetch is intentionally separate from SVG rendering. A normal generator run is offline and reproducible from the profile and snapshots. Refreshing a catalog may change results because the upstream archives evolve.

curated-sky.json adds a small multi-wavelength deep-sky collection and the GCN transient snapshot associated with the checked-in timestamp. Its source URLs preserve provenance for every item. JAXA Earth data is owned by the separate Cloud-atmosphere generator and is not used as a celestial-position catalog. Astronomy and Cloud-atmosphere share the solar ephemeris, but not their observations or coordinate domains.

The Solar System calculations are visualization-grade. Major-planet positions use the JPL Solar System Dynamics approximate Keplerian elements valid from 1800 through 2050. Small bodies use the osculating elements in their SBDB snapshots and a two-body propagation. These results must not be used for telescope pointing, navigation, occultation prediction, or other precision work; JPL Horizons or SPICE is required for those uses.

Major planets use JPL equatorial radii and calculated geocentric distances to draw a dotted outline at true apparent angular size. Their legibility glyph is separate, fixed at 0.15 inch—twice the former 0.075-inch symbol. Metadata and per-object attributes distinguish the physical outline from this display scale.