{"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":"2026-08-27T20:41:29.452Z","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":"thuban","name":"Thuban","class":"a0iii_white_giant","category":"star","object_type":"A0III white giant","mag":3.67,"mag_band":"V","abs_mag":-1.171,"abs_mag_band":"V","distance_ly":303.11930044585444,"distance_method":"parallax","ra_deg":211.097475,"dec_deg":64.37585,"epoch_ra_deg":211.28367,"epoch_dec_deg":64.246936,"epoch_moved_arcsec":1.575,"pm_ra_mas_yr":-56.52,"pm_dec_mas_yr":17.19,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Draco","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/thuban","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wikidata_id":"Q15714","also_known_as":["Right Pivot"],"spectral_type":"A0III","uncertainties":{"metallicity_fe_h":[0.68,0.68]},"color_index_bv":-0.049,"luminosity_solar":256.09435171567696,"metallicity_fe_h":0.12,"wikipedia_article":"Thuban","radial_velocity_km_s":-13,"spectral_type_source":"SIMBAD (2024A&A...690A.176N, quality C)","surface_gravity_log_g":2.9,"surface_temperature_k":10080,"metallicity_fe_h_source":"Median of 2 spectroscopic determinations in 3 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-56.52,"proper_motion_dec_mas_yr":17.19,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"11 Alpha Dra"},{"catalog":"Common name","designation":"Thuban"},{"catalog":"HD","designation":"HD 123299"},{"catalog":"HIP","designation":"HIP 68756"},{"catalog":"HR","designation":"HR 5291"},{"catalog":"IRAS","designation":"IRAS 14030+6436"}],"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."}