{"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":"2026-09-03T21:03:28.266Z","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":"hd-27176","name":"51 Tau","class":"f0v_yellow_white_main_sequence_star","category":"star","object_type":"F0V yellow-white main-sequence star","mag":5.64,"mag_band":"V","abs_mag":1.976,"abs_mag_band":"V","distance_ly":176.3008945673862,"distance_method":"parallax","ra_deg":64.59666,"dec_deg":21.579297,"epoch_ra_deg":64.994696,"epoch_dec_deg":21.644783,"epoch_moved_arcsec":2.726,"pm_ra_mas_yr":96.42,"pm_dec_mas_yr":-33.92,"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/hd-27176","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"04184+2135","companions":[{"measured":2018,"magnitude":8.1,"components":"Aa,Ab","discoverer_code":"MCA  14","separation_arcsec":0.2,"position_angle_deg":175},{"measured":2000,"magnitude":null,"components":"Aa,Ac","discoverer_code":"LMP  52","separation_arcsec":0.3,"position_angle_deg":133},{"measured":2000,"magnitude":null,"components":"Aa,Ad","discoverer_code":"LMP  52","separation_arcsec":0.3,"position_angle_deg":270},{"measured":2015,"magnitude":10.35,"components":"AB","discoverer_code":"BUP  52","separation_arcsec":158.7,"position_angle_deg":61}],"spectral_type":"F0V","color_index_bv":0.277,"luminosity_solar":14.112371484118507,"radial_velocity_km_s":35,"spectral_type_source":"SIMBAD (quality C)","surface_temperature_k":7328,"proper_motion_ra_mas_yr":96.42,"proper_motion_dec_mas_yr":-33.92,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"51 Tau"},{"catalog":"HD","designation":"HD 27176"},{"catalog":"HIP","designation":"HIP 20087"},{"catalog":"HR","designation":"HR 1331"}],"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."}