{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T23:06:16.439Z","years_from_j2000":26.654,"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-3384","name":"HD 3384","class":"g0_yellow_star","category":"star","object_type":"G0 yellow star","mag":8.88,"mag_band":"V","abs_mag":1.607,"abs_mag_band":"V","distance_ly":929.2204985841352,"distance_method":"parallax","ra_deg":9.232755,"dec_deg":22.303574,"epoch_ra_deg":9.585989,"epoch_dec_deg":22.451297,"epoch_moved_arcsec":0.647,"pm_ra_mas_yr":20.97,"pm_dec_mas_yr":-12.2,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Andromeda","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-3384","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":1088141800,"mass_solar":2.03,"radius_solar":4.795,"spectral_type":"G0","color_index_bv":0.611,"luminosity_solar":19.824397628726402,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1993yCat.3135....0C, quality E)","surface_gravity_log_g":3.287,"surface_temperature_k":5828,"proper_motion_ra_mas_yr":20.97,"proper_motion_dec_mas_yr":-12.2,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":21.861},"designations":[{"catalog":"HD","designation":"HD 3384"},{"catalog":"HIP","designation":"HIP 2915"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-27T19:16:43.430Z","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."}