{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.666","julian_year":2026.666,"time":"2026-09-01T09:19:05.832Z","years_from_j2000":26.666,"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-1685","name":"π Tuc","class":"b9v_blue_white_main_sequence_star","category":"star","object_type":"B9V blue-white main-sequence star","mag":5.5,"mag_band":"V","abs_mag":0.554,"abs_mag_band":"V","distance_ly":318.2014236642321,"distance_method":"parallax","ra_deg":5.162669999999999,"dec_deg":-69.624913,"epoch_ra_deg":5.475595,"epoch_dec_deg":-69.475886,"epoch_moved_arcsec":0.108,"pm_ra_mas_yr":-4.01,"pm_dec_mas_yr":-0.64,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Tucana","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-1685","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"00207-6938","age_years":298201350,"companions":[{"measured":2016,"magnitude":10.1,"components":null,"discoverer_code":"HUB   1","separation_arcsec":2.3,"position_angle_deg":216}],"mass_solar":2.709,"radius_solar":2.747,"spectral_type":"B9V","color_index_bv":-0.046,"luminosity_solar":52.28775553134414,"radial_velocity_km_s":12,"spectral_type_source":"SIMBAD (1975MSS...C01....0H, quality C)","surface_gravity_log_g":3.88,"surface_temperature_k":10421,"proper_motion_ra_mas_yr":-4.01,"proper_motion_dec_mas_yr":-0.64,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: above 7,500 K GSP-Phot's temperature and extinction are degenerate","bolometric_luminosity_solar":73.7179},"designations":[{"catalog":"Bayer/Flamsteed","designation":"Pi Tuc"},{"catalog":"HD","designation":"HD 1685"},{"catalog":"HIP","designation":"HIP 1647"},{"catalog":"HR","designation":"HR 83"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}