{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T19:43:27.313Z","years_from_j2000":26.673,"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":"hip-21745","name":"HIP 21745","class":"yellow_white_star","category":"star","object_type":"Yellow-white star","mag":10.32,"mag_band":"V","abs_mag":4.103,"abs_mag_band":"V","distance_ly":571.2019043282431,"distance_method":"parallax","ra_deg":70.032555,"dec_deg":3.322727,"epoch_ra_deg":70.384736,"epoch_dec_deg":3.37552,"epoch_moved_arcsec":0.256,"pm_ra_mas_yr":-9.38,"pm_dec_mas_yr":2.11,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Taurus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hip-21745","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":1849455500,"mass_solar":1.63,"radius_solar":2.598,"color_index_bv":0.533,"luminosity_solar":1.989756811090657,"radial_velocity_km_s":0,"surface_gravity_log_g":3.699,"surface_temperature_k":6208,"proper_motion_ra_mas_yr":-9.38,"proper_motion_dec_mas_yr":2.11,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":10.3503},"designations":[{"catalog":"HIP","designation":"HIP 21745"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","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."}