{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T12:32:42.081Z","years_from_j2000":26.669,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, and the result is referred to the true equator and equinox of this instant. Those are separate things: the motion moves the object, and the rotation turns the grid under it by about fifty arcseconds a year, with nutation adding up to another seventeen.","excluded":"Parallax, the radial-velocity perspective term, aberration and refraction; each is below the accuracy of the catalogued positions themselves. An object with no published proper motion comes back where the catalogue has it rather than at a fabricated zero, and says so with a null pm_ra_mas_yr. A body with no fixed position is not propagated at all — its place comes from an ephemeris, which is what /api/v1/visible answers with."},"slug":"hd-20731","name":"HD 20731","class":"k0iii_orange_giant","category":"star","object_type":"K0III orange giant","mag":9.09,"mag_band":"V","abs_mag":0.802,"abs_mag_band":"V","distance_ly":1482.52913787446,"distance_method":"parallax","ra_deg":49.59927,"dec_deg":-48.996489,"epoch_ra_deg":49.814095,"epoch_dec_deg":-48.898056,"epoch_moved_arcsec":0.044,"pm_ra_mas_yr":1.01,"pm_dec_mas_yr":1.29,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Horologium","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-20731","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"K0III","color_index_bv":0.999,"luminosity_solar":41.61021885174549,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1978MSS...C02....0H, quality C)","proper_motion_ra_mas_yr":1.01,"proper_motion_dec_mas_yr":1.29},"designations":[{"catalog":"HD","designation":"HD 20731"},{"catalog":"HIP","designation":"HIP 15387"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}